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WATER POLLUTION CONTROL RESEARCH SERIES 



Deep Tunnels in Hard Rock 



U.S. ENVIRONMENTAL PROTECTION AGENCY 






WATER POLLUTION CONTROL RESEARCH SERIES 


The Water Pollution Control Research Series describes 
the results and progress in the control and abatement 
of pollution in our Nation's waters. They provide a 
central source of information on the research, develop¬ 
ment, and demonstration activities in the Environmental 
Protection Agency, through inhouse research and grants 
and contracts with Federal, State, and local agencies, 
research institutions, and industrial organizations. 

Inquiries pertaining to Water Pollution Control Research 
Reports should be directed to the Chief, Publications 
Branch, Research Information Division, Research and 
Monitoring, Environmental Protection Agency, Washington, 
D. C. 20460. 



t 




Proceedings 

from 


DEEP TUNNELS IN HAND ROCK 
A Solution to Combined Sewer Overflow and 
Flooding Problems 


An Engineering Institute 
Presented By- 


College of Applied Science and Engineering 
The University of Wisconsin-Milwaukee 


and 


University Extension 
The University of Wisconsin 


Civic Center Campus 
November 9-10, 1970 
Milwaukee, Wisconsin 


For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.75 



1 


-fDiz 1 



c 


EPA Review Notice 


This report has been reviewed by the Environmental Protection 
Agency and approved for publication. Approval does not 
signify that the contents necessarily reflect the views and 
policies of the Environmental Protection Agency nor does 
mention of trade names or commercial products constitute 
endorsement or recommendation for use. 


ii 



ABSTRACT 


The Proceedings which follow contain the information presented at an 
institute held at the Civic Center Campus of the University of Wisconsin 
Milwaukee (UWM), on November 9-10? 1970. The program was conducted by 
the University Extension under the technical guidance of the College of 
Applied Science and Engineering at UWM. Arrangements for the program 
and compilation of these Proceedings were completed under the supervision 
of Professors Vinton W. Bacon and Paul A. Seaburg. 

These proceedings are published by the Office of Research and Monitoring, 
Environmental Protection Agency. 


• • • 
m 






CONTENTS 


SESSION 1 

PROBLEM DEFINITION AND CURRENT SOLUTIONS PAGE 

SECTION 1 

THE FLOODING AND COMBINED SEWER OVERFLOW 

PROBLEM IN URBAN METRO AREAS 

Vinton W. Bacon 3 

SECTION 2 

METROPOLITAN SANITARY DISTRICT OF GREATER 

CHICAGO EXPERIENCES AND FUTURE PLANS FOR 

HARD ROCK TUNNELS 

Forrest Neil 9 

SESSION 2 

MULTIPLE PURPOSE BENEFITS OF DEEP STORAGE 

AND TUNNELING 

SECTION 3 

THE ROLE OF STORAGE IN ECONOMICS OF SEWAGE 

TREATMENT PLANT DESIGN 

William J. Bauer 33 

SECTION 4 

THE IMPACT OF THE DEEP TUNNEL PLAN ON WATER 

RESOURCES IN THE CHICAGO AREA 

Victor Koelzer 49 

SECTION 5 

THE POTENTIAL OF PUMPED STORAGE FOR HYDRO¬ 
ELECTRIC GENERATION IN MULTI-LEVEL DEEP 

TUNNEL SYSTEMS 

Kenneth E. Sorenson 79 

SESSION 3 

EXPERIENCES WITH HARD ROCK TUNNELING AND 

MECHANICAL MOLES 

SECTION 6 

EUROPEAN DEVELOPMENT AND EXPERIENCE WITH 

MECHANICAL MOLES IN HARD ROCK TUNNELING 

Pieter Barendsen 93 

SECTION 7 

EUROPEAN DEVELOPMENT AND EXPERIENCE WITH 

MECHANICAL MOLES IN HARD ROCK TUNNELING 

Ernst Weber 113 

SECTION 8 

EXPERIENCE IN EDMONTON CANADA WITH EMPHASIS 

ON PNEUMATIC CONVEYANCE OF MUCK 

C. G. Chrysanthou 131 


v 


CONTENTS 


SESSION 4 

SECTION 9 

SECTION 10 

SECTION 11 


GEOLOGY AND STATE-OF-THE-ART PAGE 

GEOLOGIC EXPLORATION FOR CHICAGOLAND AND 
OTHER DEEP ROCK TUNNELS TO BE CONSTRUCTED 
BY MECHANICAL MOLES 

George E. Heim, R, W. Mossman, Homer Lawrence 

THE CONTRACTORS VIEWPOINT OF THE HARD ROCK 
MECHANICAL MOLE - WHAT'S CAUSING DOWNTIME? 

WHAT DO THEY WANT? 

Victor L. Stevens 175 

RAPID EXCAVATION IN HARD ROCK: A STATE-OF- 
THE-ART REPORT 

William E. Bruce, Roger Morrell 187 


vi 


Session 1 


PROBLEM DEFINITION AND CURRENT SOLUTIONS 


Moderator 


W. A. Rosenkranz 






















Section 1 


THE FLOODING AND COMBINED SEWER OVERFLOW FROBLEM 

IN URBAN METRO AREAS 

by 

Vinton W. Bacon 
Professor of Civil Engineering 
University of Wisconsin 
Milwaukee, Wisconsin 53211 


3 






THE FLOODING AND COMBINED SEWER OVERFLOW 
PROBLEM IN URBAN METRO AREAS 


What is the magnitude of the combined-sewer problem in the United 
States? The most authoritative estimate in the U. S. was made 
in 1967 by the American Public Works Association under the sponsor¬ 
ship of the Federal Water Quality Administration of which our 
moderator, Mr. William Rosenkranz, is representative. 

It is estimated that in the U. S. there are 1,329 jurisdictions, 
served in whole or in part by combined sewers, having a total 
population of 54 million. Of this projected population, it is 
estimated that 36 million are actually served by combined sewers. 
Typical are the heavily built-up, central cores in cities such 
as Milwaukee, Chicago, Cleveland, Minneapol is-St. Paul, 

Washington, D.C., New York, Boston, San Francisco, St. Louis, 
and many, many others. 

Although the gallonage of sewage overflow is only about 5% of 
the total, it is estimated that about 30% of the total pollution 
material is overflowed to the waterway. This occurs because 
large storm sewers are laid on flat grades, causing low velocity 
and settling of much of the sewage solids within the pipes. The 
high velocities of storm flows scour up the material, carrying 
it to the waterway with the overflow. Thus in magnitude, 
tremendous quantities of pollutants are flushed from combined 
sewers. 

The combined sewer overflow problem can be solved in one of three 
ways, or a combination of the three. 

First, sewers can be separated, that is, a second sewer can be 
constructed in the street. In built-up cities, this would take 
years to complete and construction would occur in all of the 
combined sewer areas. Politically, it is doubtful if administrations 
attempting this solution would survive more than one term. Further, 
it is extremely costly. APWA estimates that if all jurisdictions 
were to solve the problem through separation that the total ex¬ 
penditure would approximate $30 billion and to make the necessary 
changes in and on private property to effect total separation would 
increase this total cost to approximately $48 billion. Responses 
from many of the municipalities surveyed, especially those with 
high population densities, disclose that the possibility of 
changing all combined sewers to separate is remote. 

Chicago alone estimates that the cost of separation together with 
the property connections would cost in excess $4 billion to eliminate 


5 


the effects of the 400 overflow points. Chicago has concluded 
not to try separation in the combined area. 

Secondly, treatment can be provided at the point of overflow simply 
by interception before discharge. Treatment could be by primary 
settling, screening, aeration, disinfection, and other means. A 
number of worthy demonstration projects for this system are under¬ 
way throughout the U. S., including Milwaukee. Because the overflow 
points are usually in built-up areas, one of the difficulties is 
the availability of land. This is likely to limit this application. 

Having seen sewer separation as politically impractical and too 
costly, and having seen limitations of overflow interception and 
treatment, both Boston and Chicago, studying independently, developed 
an innovative solution. Both cities looked to the underground for 
space for the solution, and both separately came to the same con¬ 
clusion: build conveyance tunnels (sewers) and storage caverns in 
the underground rock. By building tunnels under the present rivers 
in Chicago the overflow at 400 points can be intercepted by vertical 
drop shafts, thus allowing only "clean" surface runoff to the 
river system. The polluted combined sewer overflow would be stored 
during the storm, pumped back to the surface after the storm, and 
treated in existing or new plants. Nothing really new, except the 
configuration of the component parts. Underground pumping stations, 
room-and-pillar mining, circular tunnels mined in hard rock with 
mechanical mining machines, and other features have all been used 
and proved elsewhere. 

This Institute on "Deep Tunnels in Hard Rock - A Solution to Combined 
Sewer Overflow and Flooding Problems" is based on 5 major convictions 

1. The combined-sewer overflow problem, with the attendant 
flooding problem, in metropolitan urban areas must be 
solved if the new and stringent State and Federal water 
quality standards are to be met. Secondary, tertiary, and 
advanced waste-water treatment of dry-weather flows will 

be a waste of money if the overwhelming raw-waste pollution 
of combined-sewer overflows, is not likewise controlled. 

2. Of the three apparent solutions (sewer separation, retention 
and treatment at the overflow points, and underground 
conveyance and storage), the latter provides the cheapest 
and most complete solution where rock strata conditions 

are favorable. 

Retention and treatment at overflow points, such as being 
developed and demonstrated here in Milwaukee, either 


6 


separately or in combination with tunnel and storage 
facilities, has great merit, too. 

Sewer separation in older, highly developed, and congested 
urban areas appears to have little to recommend it. 

3. Key to the underground conveyance and storage solution is 
rapid and less costly excavation of tunnels in hard rock. 

4. Key to such rapid excavation is the mechanical mining 
machine for circular or other tunnel configurations. 

5. And lastly, the mechanical mining machine has demonstrated, 
possibly in a fledgling manner, that it can provide more 
rapid excavation and at less cost then other methods 
heretofore standard in tunnel construction. 

With such convictions, what are the hoped-for goals of this Institute? 

First, we want to hear of the successful recent experiences in 
Chicago, Western United States, Canada, Europe, and elsewhere. 
Through the mere recitation of such experience sharing, we hope 
to give impetus to further development and application and 
cost reduction. 

Secondly, we hope to develop some of the multiple-use aspects 
of the deep-tunnel solutions, such as, pumped storage for 
hydroelectric storage, storage as a substitute for waste treat¬ 
ment plant capacity, the impact of storage on the water resources 
of an area, and the impact of the system on recreation, navigation, 
and other beneficial uses. 

Third, we hope to assess the future of rapid excavation in hard 
rock by mechanical mining through the opinions of machine manu¬ 
facturers, construction contractors, directors of public work, 
consultants, educators, and government. 

Lastly, we hope to encourage those facing combined sewer and 
flooding problems to assess the potential use of tunnels in 
their areas, believing that this system is in its infancy and 
needful of the creative thinking of many. Boston, as Chicago, 
has concluded, after extensive engineering studies that rock 
tunnels provide the solution for that metropolitan area. 


7 




















































































Section 2 

METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO 
EXPERIENCES AND FUTURE PLANS FOR HARD ROCK TUNNELS 

by 

Forrest Neil 
Acting Chief Engineer 

Metropolitan Sanitary District of Greater Chicago 
Chicago, Illinois 6061.I 


9 


GENERAL INFORMATION 


The Metropolitan Sanitary District of Greater Chicago is a municipal 
corporation serving 5,500,000 persons living within a 860-square mile 
area in Cook County, Illinois. There are approximately 118 
municipalities, including the City of Chicago, and 30 sanitary 
districts under its jurisdiction. 

Early sewer systems, developed prior to the turn of the century to 
serve the City of Chicago and the peripheral suburbs, were combined. 
They discharged untreated flows directly into the waterways, which, 
in turn, flowed into Lake Michigan - polluting the source of water 
supply for Chicago and many of the suburbs. 

To protect the water supply, the Metropolitan Sanitary District was 
organized in 1889. Drainage in the Chicago River Basin and the 
Calumet River Basin was diverted from Lake Michigan (St. Lawrence 
River Watershed) into the Des Plaines River (Mississippi Watershed). 
This was accomplished by construction of the Sanitary and Ship Canal 
in 1911, which served the northern suburbs of Chicago; and the Cal 
Sag Channel in 1923, which reversed the Calumet River System. Three 
control structures prevent the river and canal system from flowing 
into the lake and permit the entrance of lake water to the system. 

The canal system, in addition to providing pollution and flood control, 
is a major shipping artery for bulk commodities. (Fig. 1) 

At one time up to 9,000 cfs were diverted from Lake Michigan into the 
canal system to dilute the sewage. In 1925 several states instituted 
a suit against the State of Illinois and the Metropolitan Sanitary 
District to limit diversion. It was heard by Special Master Hughes 
for the Supreme Court of the United States. The court issued a 
decree in 1930. The decree forces the Metropolitan Sanitary District 
to increase its program of construction of plants and intercepting 
sewers so that it would be able to reduce diversion to 1,500 cfs by 
1940 for all purposes except water supply. 

On June 30, 1967, the State of Illinois adopted water quality 
standards. These were subsequently approved by the Federal Government. 
These standards require that canals presently used for industrial 
cooling water supply, shipping and waste assimilation be upgraded to 
where they car, be used for water supply and recreation. 

The B.O.D., suspended solids, and other parameters in municipal 
treatment plant effluent, industrial waste discharges and combined 
sewer overflows exceed the assimilation capacity of the canal and 
river system. None of the major waterways meet the standards. 


10 


The adoption of the standards and limitation of diversion waters by 
decree have forced the Metropolitan Sanitary District to include 
tertiary treatment at its plants and an equivalent of separation of 
sewers in combined sewer areas in the future program. The diversion 
will be further reduced, increasing the severity of the problem, as 
other communities and sanitary districts request an additional share 
of the 3,200 cfs for water supply and diversion of sewage effluent 
from the lake. 

The Metropolitan Sanitary District has proposed a $2 billion-dollar, 
ten-year program to meet the water quality standards and permit higher 
uses of the waterways. 


COMBINED SEWER PROBLEM 

In the City of Chicago and older suburbs, there are over 300 square 
miles (Fig. 2) served by combined sewers. These areas are almost fully 
developed - having only about 12% vacant property. Many industries 
using large quantities of water are located in these areas. 

Most of the Suburban combined sewer systems discharge their storm 
overflow to the local streams. These streams flow through Forest 
Preserves or other recreational areas. Swimming or wading cannot be 
permitted due to the polluted condition. Fishing is limited to a 
very few areas. 

The greatest number of the 400 overflow points (Fig. 3) from combined 
sewers discharge directly to the canal system. Use of canal water is 
generally restricted to cooling water due to the poor water quality. 

The cost of separation of sewers would be over $4 billion-dollars. 
Disruption of the community and loss of business during the construction 
would add considerable expense to this figure. 

Based on present knowledge of storm runoff from urban areas it is 
doubtful if separation would sufficiently improve the quality of the 
waterways to meet standards. 


FLOOD CONTROL PROBLEM 

The Metropolitan Sanitary District has the responsibility of providing 
outlet capacity for drainage from the Greater Chicago area. The 
canal system, which discharges through a control structure and power 
house into the Des Plaines River at Lockport, and the upper portion 
of the Des Plaines River and its tributaries are the main stormwater 
out!ets. 


11 


Rapid urbanization of tha area is increasing runoff and peak flows in 
the waterways. This, is illustrated by the fact that the Metropolitan 
Sanitary District has had to permit the canal system to flow to the 
lake on eight occasions during severe storms in the last ten years to 
prevent flooding. 

No major improvements to increase the outlet capacity have been made 
to the Sanitary and Ship Canal or the Des Plaines River since their 
original construction. Additional capacity in the canal and river 
system must be provided by deepening and widening, or stormwaters must 
be detained and gradually released after the peak of the storm. 

Failure to do this will cause storm flows to be released into Lake 
Michigan with increasing frequency - a violation of the standards and 
our ordinances. 

Retention of storm flows in surface reservoirs has been a standard 
flood control practice for many years. The Metropolitan Sanitary 
District has constructed, has participated in the construction of and 
has future plans for approximately 15 surface reservoirs on the 
smaller streams. These are primarily in the separate sewered areas. 

In the combined sewer area, the flat topography, development of the 
area, and cost of land limit the number of reservoir sites, therefore, 
investigation of the potential of subsurface storage becomes desirable. 
This would include rock tunnels and storage areas. 


EQUIVALENT OF SEWER SEPARATION - DEEP TUNNEL PLAN (Fig. 4) 

It must be emphasized to meet water quality standards we must 
collect and treat overflows from the combined sewer area. Conveyance 
tunnels and storage reservoirs will be required. 

Basically, the plan provides for intercepting the combined sewer over¬ 
flow ahead of the outfall, diverting it into conveyance tunnels and 
storing the flow in underground and surface reservoirs. It would then 
be treated at existing and new plants before discharge to the waterway. 

Several plans for equivalent of sewer separation have been reviewed. 

The two basic plans - which are being merged at the present time - 
are the Deep Tunnel Plan proposed by the Metropolitan Sanitary 
District, and a composite plan proposed by the City of Chicago (Fig. 5). 
It has been agreed among engineers in these agencies that underground 
rock tunnels, combined with storage underground and on the surface, is 
the most feasible method. Both plans have these features. The City 
of Chicago has been engaged by the Metropolitan Sanitary District to 
develop a plan for 11 miles along the North Branch of the Chicago River 
and the North Shore Channel and prepare plans and specifications for 
the initial contract. The work in this area can be designed to be 
compatible with variable plans which may be decided upon downstream. 

The first tunnels will be constructed within the Niagaran rock formation. 


12 


Tunnels paralleling the waterways are proposed which will intercept 
the overflows. The tunnels will provide storage as well as transport. 

In addition, large storage reservoirs on the surface and in the rock 
are proposed in the vicinity of our major sewage treatment works. 

These storage reservoirs will permit combined sewage to be treated 
after the storm using peaking capabilities of the plants. 

The three rock tunnels presently under construction can be incorporated 
into the projects. Their point of discharge would be to a conveyance 
tunnel below them which would greatly increase the discharge capacity 
due to the additional head available. The construction of these projects 
is proving the feasibility of using rock moles for tunneling in lime¬ 
stone. 


RELIEF INTERCEPTING SEWERS (Fig. 6) 

Due to the rapid expansion of the Metropolitan Sanitary District in 
area, population, residential, commerical and industrial development 
in the last 15 years, relief sewers are required to convey the waste 
to our treatment plants. The District doubled in size in 1956. To 
provide immediate service, future capacity in the then existing 
intercepting sewers was committed to serving the newly annexed areas. 
Relief sewers, at a projected cost of $100,000,000 are planned through¬ 
out the Metropolitan Sanitary District to provide service when the 
area is fully developed. 

The Metropolitan Sanitary District is presently proposing using the 
same deep or underflow tunnels, which will convey the combined sewage, 
as relief sewers to take quantities in excess of the dry weather flow 
capacity of the existing interceptors. This will eliminate the need 
of a parallel relief sewer at a higher level to convey the flows to 
the sewage treatment plants. The tunnels and storage areas will also 
enable the Metropolitan Sanitary District to reduce or practically 
eliminate the hourly fluctuation in sewage flows at the plants. By 
having an even flow through the plant, a better effluent can be 
maintained, as one of the variables of plant operations is controlled. 

Mining storage reservoirs, using multiple headings, is believed to be 
economical. The underground quarrying of limestone has been done else¬ 
where in the nation. Cost estimates which we are presently reviewing 
indicate less than the $5/yard we have in our initial studies. The 
industry already has developed the equipment required. 


TREATMENT FACILITIES 

As we will be mining tunnels and storage areas in the rock under our 
plants, the advantages and disadvantages of constructing treatment 
facilities underground are being investigated. If the areas for 
treatment facilities are mined at the same time as the tunnels, the 


13 


cost would be reduced due to the large cost of setting up a mining 
operation. 

There are advantages in the suhsurface which include: 

1. Having limited space at the existing plant sites, additional 
land will be needed to meet the requirement of tertiary treatment 
and treating combined sewer overflow. Underground construction 
should minimize the additional land required. Land in the vicinity 
of the existing plants is very expensive and largely developed. 

2. Tests indicate oxygen transfer is speeded up under pressure. By 
using the available head in a siphon arrangement, it may be possible 
to cut aeration time thereby reducing the size of facility required 
and cost of mining below ground. 

As we presently believe the only practical method of removing ammonia 
is to nitrify, we are considering additional batteries of aeration and 
final tanks to provide two-stage aeration at our major plants. This 
requires large sites. 

We have constructed a small pressurized activated sludge plant. 
Experiments with this unit, as well as lab experiments, will determine 
the feasibility of this concept. 


PRESENT TUNNELING EXPERIENCES 

Tunneling construction methods for water conduits, subways and sewers 
have been developed in the Chicago area over a period of many years. 
Mining machines are now extensively used in the clays and granular 
materials. Rock moles are presently being used on three major contracts 
in the Chicago area. These contracts are as follows: 

...Lawrence Avenue Tunnel, a 13'8" diameter bore, for the City of 
Chicago, being constructed by S. A. Healy at a cost of $10,792,-094. 
(Fig. 7) 

...Calumet Intercepting Sewer 18E, Extension A, a 16'10" diameter bore, 
being constructed by S&M Constructors for the Metropolitan Sanitary 
District, at a cost of $6,954,675. The cost per cubic yard 
excavation, unlined, is $33.50. (Fig. 8) 

...Southwest Intercepting Sewer 13A, a 13 1 10" diameter bore, being 
constructed by S. A. Healy and Kenny Construction Companies for the 
Metropolitan Sanitary District, at a cost of $6,210,736. The cost 
per cubic yard excavation, unlined, is $50.09. (Fig. 9) 

These projects are in the Niagaran limestone formation and are 
located approximately 200 ft. below the surface. They are proving the 
effectiveness of the rock moles in the Chicago region. The rock is 


l4 


structurally sound, which eliminates the need for a conventional con¬ 
crete lining for structural support. The contractor is required to 
grout and stop any leaks which, occur. After completion of the mining, 
the tunnels will be inspected to determine what surface treatment, if 1 
any, will be required. 

A Jarva machine was used on the Calumet 18E Ext. A sewer. The mining 
is nearly complete. The average progress per hour was 4.9 ft. A 
Robbins mining machine was used on the Southwest 13A Contract. The 
mining is presently completed. (Fig. #10) 

Infiltration enters the project from the shafts, line holes, some of the 
horizontal bedding planes and vertical faults. No grouting was per¬ 
formed during construction on the Calumet 18E Ext. A job. Portions of 
the Southwest 13A project were grouted before and during the mining 
operation. After the mining of these tunnels, additional grouting is 
required. 

These tunnels are designed as siphons which will discharge to the water¬ 
way during all but the smaller storms. They will be de-watered by a 
pumping station after the storm into an intercepting sewer, which will 
convey the flow to a major sewage treatment plant. The storage in the 
system is used in this manner to reduce the pollutants discharged to the 
stream. 

In our area experience with rock moles is limited to about 3 years. Im¬ 
provements are continually being made. It is expected that the next 
generation of machines will greatly improve operations and procedures. 


GEOLOGY OF REGION 

The upper strata consist mostly of tills, lacustrine clays with some 
stratified deposits and sand dunes (Fig. #11). The Niagaran and Galena 
Platteville limestone formations underlie the urban area - separated by 
a shale formation - the Niagaran being approximately 0 to 300 ft, below 
the surface. To date, except for quarrying from the surface in the 
Niagaran and construction of water tunnels and a small number of wells, 
little use has been made of the limestone formations. 

In the last few years, over $1,925,000 have been expended on investiga¬ 
tions which included seismic, drill holes and rock cores, and logging 
existing and.new wells. Additional information will be obtained as new 
tunnel alignments are decided upon. The data have provided substantial 
information on the rock strata. 


SUMMARY 

Space is at a premium in metropolitan areas. Surface reservior sites 


15 


for flood and pollution control are limited in number and costly. Where 
subsurface projects can be constructed at prices competitive with more 
conventional surface solutions and having additional benefits, they 
should be carefully evaluated. 

Underground construction provides advantages that should be considered 
in urban areas. 

1. It greatly reduces the disruption of an urban community. Utilities 
are generally not affected as they are with open-cut work. The 
costs of moving utilities are generally assumed by the utility com¬ 
pany. This is a cost which is not reflected when open-cut and tun¬ 
neling estimates are compared. There is little inconvenience to 
residents compared with open-cut work. The construction does not 
interfere with the operation of existing commercial and industrial 
establishments. 

2. As a part of a system, the deep tunnel can provide an equivalent of 
sewer separation. This will improve water quality and enable the 
area to meet established water quality criteria. The cost should be 
less than 25% of the cost of sewer separation. Due to the pollution 
in storm runoff from urban areas, sewer separation would not suffi¬ 
ciently improve the quality in the waterways to meet the established 
standards. The system could be enlarged to handle polluted runoff 
from separate sewer areas. 

3. Providing an outlet far below the existing local sewer systems will 
improve their performance and permit much more flexibility and 
economy in the design of relief systems in the local communities. 

4. Collecting, storing and treating combined sewage before releasing 
to the canal will reduce the amount of diversion water required to 
meet the standards. This is of great importance as the demand for 
lake water in Northeastern Illinois increases. 

5. The large volumes of underground storage provide a means of reducing 
peak flows in the channel system - eliminating the need for dis¬ 
charge of contaminated water to Lake Michigan in severe storms as 
has been required in the past. It should reduce or eliminate the 
need for major widening and deepening of the waterways. 

6. The mined rock from many of these projects can be stored in existing 
quarries for future commercial sale, used to create additional park 
land or in the lake airport which is under consideration, used to 
create a recreational mountain in this flat region, etc. Many of 
these uses provide a benefit that can be measured in dollars - re¬ 
ducing the cost of the projects. 

7. Surface and underground reserviors can permit regulation of flows 
to the treatment plants - greatly improving their operational effi¬ 
ciencies . 


16 


8. Underground construction can permit greater expansion of plant 
facilities at existing sites. 

9 Improvements in design in tunneling equipment are going to further 
reduce the price of excavation. 


QUESTION: 


NEIL: 


QUESTION: 


NEIL: 


QUESTION: 


NEIL: 


QUESTION: 

NEIL: 


ROSENKRANZ: 

QUESTION; 


NEIL; 


How will solids be handled in the tunnels or room and pillar 
type storage? 

We felt that as a part of the design of the deep tunnel sys¬ 
tem we would need some settling tanks for the removal of 
solids. We do not have the complete answer as yet, but we 
feel it would be easier to collect solids prior to entering 
the tunnel. The requirements for aeration and the length 
of holding time in the underground storage areas are being 
studied. 

What are the differences between the underflow storage plan, 
the deep tunnel plan and the Chicago drainage plan? 

The basic differences between the deep tunnel and underflow 
plans is the amount of storage. The deep tunnel plan has 
about 60,000 acre feet to collect all overflow, the under¬ 
flow plan has about 20,000 acre feet. The drainage plan 
involves treatment at 400 overflow points and increasing 
the capacity of the canal system. 

How many miles of tunnels do you envision in the final sys¬ 
tem and how many are now under design for the next phase? 

Currently eleven miles are planned. The total tunnel system 
for Chicago only would be from 40 to 50 miles. Including 
the suburbs the system would be in the hundreds of miles. 

What techniques will be used for constructing the shafts? 

A conventional mining technique has been used. Future con¬ 
tracts may work either from the top down or the bottom up; 
this will be left as an option. 

The hydraulics of the down shafts are critical and are being 
studied. The FWQA has initiated some work at the University 
of Minnesota. 

What are the legal implications of tunneling under private 
property? 

We try to stay under public streets, otherwise we obtain 
an easement with the owner. 


17 


I 




18 


Fig. 1 


ILLINOIS - INDIANA STATE LINE 


















































-_r 


1 V 


f.i. S. O. BOUNDARY 


« KAtATias 9 




t? 


S.J" 


-r 1 


LTL 

U 


iASUiJSTCa 
g KJICSTS 


*h 


g KOU8T3L, \ 

S-J-^VK 


M. S. D. BOUNDARY 


ScgIo: p 


AREA OF COMBINED SEWERS 




A 

Li 

E A ftp 

Ld Ism kib 

| 

bicep*" 





BOUNDARY 


AREA SERVE© BY 


E© 

SEWERS 

-n 

c -J 





J 



f.1. S. D. 


iy 


Fig. 2 


1MI1 HV1S tHVIGNI • SIORIllI 























































20 


Fig. 3 































































































































































•rsa 

! * 
y 




POLL 



~ .n 

m wi 


22 




A r n r~\ 
H L 'J iis£ 


1 



















































































THE METROPOLITAN SANITARY GREATER CHICAGO 

VC HENRY CC _ LAkE CO. 

COCK CO 


LAKE 


MICHIGAN 


MIC AGO RIVIR 


"grunoy co*" 



23 


Fig. 6 


IND. 






































































ROCK TUNNEL SUMMARIES 

LAWRENCE AVE. SEVIER SYSTEM 

CONTRACT NO. 1 
« 


/ 


Length of Tunnel* 

In Lawrence Avenue. 
In Lawrence Avenue 
In Harding Avenue 


9,126 feet of 15'6V x 19'5" 
12,670 feet of 12 foot dia. 

3 ? 958 feet of 12 foot dia. 

25,764 feet 

*6,760 feet mined by machine to 
13'8" and enlarged by drill and 
blast method and 2,366 feet full 
face drill and blast with finishec 
section of 8" liner to dimensions 
of 15'6V' x IQ’S" 


Depth below Ground 245 feet max, 220 feet min 

Slope of Sewer 2.5 per 1000 


O.S. Diameter specified: (Mined by Machine): 

In Lawrence Ave. (1st 9,126) 18'4" dia. 
In Lawrence Avo.(last 12,670') 13'4? dia. 
In Harding Ave.(3,968?) 13'4" dia. 


O.S. Diameter Actual* 



In Lawrence Ave.(1st 

9,126') 

16'10*5 M x 20'9" D&B or enlarged 
from machine bore of 13'8" 

In Lawrence Ave.(2nd 

12,670') 

13'9" dia. 

In Harding Ave. 


13'9" dia. 


I.S. Diameter* 


In Lawrence Ave. (1st 9,126') 15' 6h m x 19*5" (lined) 

In Lawrence Ave. (2nd 12,670') 12'0" dia. (if lined) 

In Harding Ave. (3,968') 12’0" dia. (if lined) 


Tail Tunnel 61 feet 


Shaft 


27 feet dia. and 256 feet deep 


Contract Costs (Bid)t 

1. Shaft 

2. 12 foot dia. Tunnel 
17 foot dia. Tunnel 

3. 12 foot dia.' Lining 
17 foot dia. Lining 

4. Rock Bolts 

5. Wire Mash 


600,000 

4,658,640 

3,732,534 

993,280 

730,080 

67,500 

24 5,000 

$10,792,094 


TOTAL 


Fig. 7 














ROCK TUNNEL SUMMARIES 


LAWRENCE AVENUE SEWER SYSTEM 
CONTRACT NUMBER 1 


Increased Storage (without cone, 
lining in the 12' dia. sections) 
In Lawrence Ave. (west of Sta. 
In Harding Ave. 

TOTAL 

31% increase in Volume 

91+50) 16,610 cubic yards 

5,202 cubic yards 

21,812 cubic yards 


Award Date 

November 1, 1967 • 


Term of Contract 

1,095 days 


• 

Specified date of completion 

November 5, 1970 


Normal Shifts 

24 Hours Monday through Saturday 


Total Progress to date: 

Lawrence Avenue: 

Machined mined (13'-8") 

Drill and Blast Enlargement 

In Harding Avenue (13*9") 

13.094 feet 

9,126 feet 9/30/70 

9,126 feet 9/30/70 

3,968 feet 9/30/70 


Progress Max. Week 

347 feet 2 Shifts 


Progress Max. Day 

92 feet (2 Shifts) 


Maximum Penetration ft./hr. 

8.7 maximum 


Comp. Strength Rock p.s.i. 

11,400 to 29,600 



Mining Machine: 

» 

Manufactured by 

j Thrust of Machine 
Drive of Machine 
Operation Voltage 
; Make of Bits 

Number of Cutters 
Diameter of Cutterhead: 
Machine Number 1 
Machine Number 2 


Lawrence Mfg. Company 

1,300,000 lb. (Max.). 850,000 lb. oper. 
5-125 hp. motors 
480 Volts 

Lawrence Mfg. Company 
29 Disc-Type with carbide inserts 

13'"8" dia. in Lawrence Avenue 
13'”9" dia. in Harding and Lawrence 


Length of Machine: 


25 




















ROCK TUNNEL SUMMARIES 

LAWRENCE AVENUE SEWER SYSTEM 
CONTRACT NUMBER 1 


Assembly 

Drawbar 

Power Train 

Auxiliary Power,Train 

TOTAL 

lS'-ll" 

15'-H" 

23 1 -7" 

25'-4" 

84 1 - 9"" 


Tunnel Power Lino 

4,160 Volts 


.Conveyor System Manufacturer 

Lawrence Mfg. Co. with a Goodyear 

Belt 24" wide by 84' long 


•Muck Cars 

6 Cubic Yards 


Length of Train 

Track Gauge 

Locomotives 

9 Cars 

36" 

10 Ton, Plymouth 

Diesel, 86 hp. 


Venti1 at i on 

28" Vent Line 

2-40 hp Vent fans made' by the 
Joy-Axivane Co. 

14,000 CFM each. 

One 15 hp. fan at street level 
to prevent any line back pressures. 


Contractor 

J. McHugh Construction Co. 

S. A. Healy Co., and Kenny Con¬ 
struction Co. (a joint venture) 

»i 


c esident Engineer 

John Redmore 


















27 


Fig. 8 





























































































































































HINSDALE 




eberly 


.OPOLITAH SANITARY DISTRICT 




GILBERT 




ENG IN 


28 


Fig. 9 










































































ROCK TUNNEL SUMMARIES 



Lawndale Avenue & 47 St. 

SW1S 13A 

127th & Crawford Ave. 

Calumet 18E-Ext. A 

Lenqth of tunnel 

17. 

553 feet 

18.320 feet 

- 

Depth below qround 

235 

Max. 201 Min. 

223 Max. 216 

- Min. 

Slope of Sewer 

2.1 

per 1000 

1.5 per 1000 

O.S. Diameter specified 

13' 

- 4" 

16' - 4" 


O.S. Diameter Actual 

13' 

- 10" 

16' - 10" 


I.S. Diameter (if lined) 

12' 

- 0" 

15' - 0" 


Tail Tunnel 

250 

feet 

260 feet 


Shaf t 

. 30' 

and 28'x206' deep 

29' and 27'x223' deep 

Contract Costs 

Bid 

Revised 

Bid 

Revised 

1. Shaft 

2. Tunnel 

3. Lining 

4. Bulkhead 

850,000 850,000 

4,567,206 4,503,723.60* 

793,530 0 

included above 

1,000,000 
4,763,200 
1,190,476 

1 .000 

1,000,000 
4,763,200 

0 

1 ,000 

TOTAL 

6,210,736 5,350,723.60'*“ 

6,954*675 

5,764,200 


^includes credit for rock 
material and refund on 
Elec. Agreement 
($3.60/1 in. ft. credit 

on rock). 


Increased Storage 
(without Cone, lininq) 

36% increase in volume 
24.000 Cubic Yards 

26% increase in volume 
31.000 Cubic Yards 

Award Date 

June 6, 1968 

May 17. 1968 

Term of Contract 

930 days 

933 days 

Specified date of completion 

January 5. 1971 

December 16. 1970 

Normal Shifts 

24 hrs. Mon. through 

Friday 

24 hors Mon. through - 
Satu rdav 

Proqress to date 

17.553 (9/24/70) 

16.018 (9/29/70) 

Proqress Max. Week 

591 feet 

607 feet 

oqress Max. Day 

144 feet 

129 feet 


29 


Fig. 10 




























' 



• 

Lawndale Avenue 6 47th St. 

SW1S 13A 

127th & Crawford Ave.' 
Calumet 18E-Ext. A 

Maximum Penetration 

ft./hr. 

5.5 avq. 8.2 maximum 

7.6 maximum 

Comp. Strenqth Rock 

ps i . 

15.000 to 24.900 

23.500 to 39,000 

Mi ninq Mach'ne 

Manufactured by 

Thrust of Machine 
Drive of Machine 
Operation Voltage 
Make of Bits 

Number of Cutters 

Length of Machine 
Dia. of Cutterhead 


James S. Robbins & 

Assoc. Inc. 

890,000 lb. (max.) 

6-100 hp motors 

460 Volts 

James S. Robbins & 

Assoc. 

27 Disc-Type plus 

Tri- Cone 

37 feet 

13 feet 10 inches 

Jarva Inc. 

2 , 200,000 1 b. (max.) 

8-125 hp motors 

480 Volts 

Reed Drilling Tools 

54 Reed Type Q.K.C. 

35 feet 

16 feet 10 inches 

Conveyor System 
manufactured by 


Moran Engineering 

Co. 96‘ bridge con¬ 
veyor ( 20 " widebelt) 
to 132 1 (18" wide 

belt) car 1 oader 

Card Corporation 

260 feet conveyor 
supporting a 30 " belt 

Muck Ca^s 

Length of Train 
Track Gauge 
= Locomotives 


4.4 Cubic Yards 

10 cars 

24" 

10 Ton, Plymouth 

Diesel, 70 hp 

10 cubic Yards 

10 cars 

36" 

15 Ton, Plymouth 

Diesel. 160 hp 

Verti1 at ion 


30" Vent 1ine 

2-100 hp Vent fans 
@1 2,000 CFM each ' 

36" Vent 1ine 
Joy-Axivane fans 

31,000 CFM max 

Contractor 


S. A. Healy Company 
and Kenny Construction 

Co. ( a ioint venture) 

» 1 

S .6 M Contractors 

1 nc. 

Resident • nqineer 


Georqe A. Taylor 

Thomas P. Vitu11i 


30 


















Session 2 


MULTIPLE PURPOSE BENEFITS OF DEEP STORAGE AND TUNNELING 


Moderator - G. Rohlich 













Section 3 

THE ROLE OF STORAGE IN ECONOMICS OF 
SEWAGE TREATMENT PLANT DESIGN 

by 

Wi11iam J. Bauer 
Presi dent 

Bauer Engineering, Inc. 

20 North Wacker Drive 
Chicago, Illinois 60606 


33 


THE ROLE OF STORAGE IN THE ECONOMICS OF 
SEWAGE TREATMENT PLANT DESIGN 


I should like to speak about a very- simple concept, discuss some of the 
ramifications of the concept, and then attempt to answer any questions 
you may have. The basic concept is to secure a higher load factor or 
higher per cent utilization of treatment plant facilities. It has its 
parallel in the pumped storage idea applied to an electric utility. 

The variation in electric power demand is quite marked, so of course is 
the demand for treatment plant capacity. Now the significance of this 
variation is becoming greater with time, because the cost of treatment— 
that is, the number of dollars it takes to buy a million gallons per day 
capacity--is going up. We require more and more of these treatment 
plants, and we require less and less pollution to be discharged from 
them. So, if there's any way of making this expensive plant work harder, 
it seems that we should take a look at it. Obviously, the way to do 
this is with storage, and the economic choice involves the relative 
costs of water storage and treatment capacity. I shall proceed first 
with some of the graphics that I have, then I shall present some of the 
results of a study we made on this matter. 


FIG. 1 

These two curves illustrate the point that I was making about the rela¬ 
tive costs of storage and treatment capacity. Here you see one curve 
labelled "higher flow rate" and the other "lower flow rate," which would 
be associated with a higher load factor. This is merely a schematic 
representation of the fact that with primary treatment only the differ¬ 
ence in cost was small so that it was not as important to regulate flow 
through the plant. As we begin to spend more money in reducing the 
permissible pollution the spread between these curves becomes greater. 
There is getting to be a much larger cost differential as we are re¬ 
quiring more and more advanced forms of treatment. 


FIG. 2 

The scale on the left is the BOD discharged in the effluent from the 
Southwest Sewage Treatment Plant of the Metropolitan Sanitary District 
of Greater Chicago. This diagram pertains to a one-year study made by 
the Federal Water Pollution Control Administration. The scale at the 
bottom is per cent of time. Three curves are shown: The lower one 
is for typical average flows. Each one of these curves was plotted with 
the aid of daily laboratory data taken from the analysis of the effluent 
of the treatment plant. If you read the chart at a certain "per cent 
of time" on a vertical line, you will find that a higher flow going 
through the plant has, in general, a higher BOD in the effluent. So, at 
any vertical line we wish to examine, we find that superior treatment is 


34 


achieved with the lower flow rate, as one would expect. 


FIG. 3 

Here is an actual plot of data taken from a treatment plant in the sub¬ 
urban Chicago area; you can see quite a variation with pronounced peaks 
and valleys. A very sharp peak corresponds to some rain. I have drawn 
two lines; one line represents the dry weather flow, and the other 
represents 1.33 times the dry weather flow. We were examining in this 
study, on the basis of the actual historical variation in these flows, 
what volume of storage was required in order to limit the flow rate 
through the treatment plant to this flow of 1.33 times the dry weather 
flow. Some sewers have many direct connections which allow storm 
water to get into them, producing a very wide ranging fluctuation. 


FIG. 4 

This plot is taken from still another example in the Chicago suburban 
area. It is based on historical variation of flows in a two-year period 
at Bloom Township Sanitary District. Plotted vertically is the treat¬ 
ment capacity in millions of gallons per day, and across the bottom 
the storage that would be required to not exceed that flow capacity. 

This is of course the end result of the type of statistical study I 
described when discussing the preceding diagram. We analyzed two dif¬ 
ferent years; One curve represents the relationship for the '67 flows, 
and the upper one represents the '68 flows. The trend line shows that 
we could achieve the same end result with the capacity of 15 million 
gallons per day if we could store 7 million gallons as we could with 
a 20 mgd plant with no storage at all. The slope of this curve is 
obviously very important and it is something that depends on the statis¬ 
tical variation in the particular flow system. Now, if this curve is 
steep it is obvious that a great deal is gained by storage; conversely, 
if it is flat, one does not have very much incentive to store. 


FIG. 5 

These curves were developed for the Deep Tunnel Plan study for the 
Metropolitan Sanitary District of Greater Chicago. Again, you see on 
this side a measure of the amount of pollution (in this case it is the 
volume of spill). Running across the bottom again is storage. As we 
increase the storage of the system, we are able to reduce the frequency 
of spill so that the total quantity of the spill is also reduced. We 
have a family of curves here, each-for a particular sustained rate of 
flow through the treatment plant. The distance between two curves at 
any particular level is the incremental storage required to achieve 
the equivalent treatment in terms of the same volume of water spilled 


35 



into the waterway. The variation here shows, for instance, that storage 
would permit us to reduce the treatment capacity from 1500 to 375 mgd. 
That means that the treatment capacity ouid be reduced to 1/4 of what 
otherwise would be required in order to handle a given situation. I 
should like to contrast this diagram with the preceding one because the 
previous one was presumed to he a separate sewer system-one not sup¬ 
posed to have any storm water connections to it—and this one is a com¬ 
bined system. You notice a great deal more benefit from using storage 
m connection with the combined system. The effect of storage on treat¬ 
ment plant capacity depends a great deal on whether the system is sep¬ 
arate or combined. 


FIG. 6 

Now there is also a question of the effect of storage on the cost of 
transporting the water. If the collection system is rather long, one 
achieves a relatively greater economic advantage from a high per cent 
utilization of that transportation system. This diagram is a schematic 
showing (in dotted lines) a flow-regulating storage system at the head 
of a collector system, then at the treatment plant itself an additional 
storage to perform the function of even further regulating the flows 
through the treatment plant. The lower diagram illustrates the typical 
variation during a day for domestic flows giving one way of evaluating, 
on a daily basis, the effect of storage on regulating flow through the 
pi ant. 

I should like to cite some figures on the relative costs of these two 
systems: First of all, with regard to the cost of storage--this can 
vary widely, depending upon the facilities that are provided. In the 
Deep Tunnel Plan studies of the Metropolitan Sanitary District of Greater 
Chicago the bulk storage which was proposed in the mined portions of the 
plant carried a price tag of about $5 per cubic yard. That did not in¬ 
clude the cost of handling solids, and the cost of aerating the flows 
that would be stored there temporarily. If you divided the $5 (call it 
$5.40) by 27 cubic feet in a cubic yard, the result is about $.20 per 
cubic foot of space. By the time one adds facilities for handling solids, 
the cost will increase to perhaps $1, or conceivably, $1.50 per cubic 
foot of storage. On the other hand, the cost of concrete boxes with lids 
at ground levels, scraper mechanisms for handling solids, plus some 
aeration facilities would probably be in the vicinity of $5 a cubic foot. 
The range we would expect to talk about is in the neighborhood of $1.50 
to $5.00 per cubic foot, or about $40 to $135 per cubic yard, or $64,000 
per acre foot, or more. Most of the cost in the case of the underground 
system is tied up in the facilities for handling solids and aerating. 

I should like to give you some analyses here of relative costs of a 30 
million gallon per day plant, with and without storage. I have used one 
unit cost for the treatment facilities themselves and that was $400,000 
per mgd capacity. We also assume that with no storage at all, we could 
provide two times dry weather flow for the basic treatment plant capacity, 


36 





meaning that it would have a capacity of 60 million gallons per day. 

Now the 60 million gpd multiplied by the $400,000 per million gallons 
gives $24 million for the treatment plant capacity without storage. 

1 recognize that quite commonly activated sludge plants are designed 
for little more than 1.0 times dry weather flow as far as the system 
of aeration, the aeration chambers, and the biological process are 
concerned, but, that they are designed for a hydraulic capacity of 

2 or 2-1/2 times the dry weather flow. This procedure is based on an 
acceptance of a reduced level of treatment during the time in which 
the plant is overloaded. Now, one of the basic assumptions I am making 
in these analyses is that this kind of operation is not going to be 
permissible for very much longer, because it is in the same category 

as dumping or bypassing when the plant is down. So, in assigning the 
unit costs, I have said that a plant averaging 30 million gpd could be 
designed to perform well at a peak rate of 60. That is the background 
for the $24 million figure. 

Then I examined a unit cost of $45,000 per acre foot of storage capacity 
and added varying amounts of storage capacity and calculated the cor¬ 
responding reduction in treatment capacity. With 13 million gallons 
of storage capacity, the plant cost was reduced by $4 million. The 
cost of that storage was $1.8 million, so that there was a net saving 
of $2.2 million. Going still further, reducing the treatment plant 
capacity to the level corresponding to 26 million gallons of storage, 
the treatment plant was estimated to be $16 million, and the storage 
about $3.6 million, or a total of $19.6 million compared to the $24 
million for the plant without any storage. These figures, of course, 
depend entirely on the statistical relationship between the volume of 
storage and the corresponding possible reduction in treatment plant 
capacity. Obviously, it also depends upon the unit cost of storage. 

If the storage is underground (as would be a convenient location in a 
crowded urban area like Chicago) one would have an added cost of pump¬ 
ing water back up. An analyses of the amount of that storm water that 
would be passed to a lower storage zone, then pumped back up to the. 
surface during a typical year in Chicago, resulted in about 14% ratio 
of storm water volume to total water volume. 

There are some advantages to providing this storage other than possibly 
an economic one. If the rate of flow through the plant is capable of 
being controlled, the processes can be adjusted to a better degree so 
that the performance is improved. The flow into the receiving stream 
is better regulated, so that there is a higher sustained flow and fewer 
high peaks. In the event there is a mechanical breakdown in the plant, 
the storage it provides is an optional one to dump the water which 
otherwise might be directly bypassed into the stream. We did not make 
a statistical study to obtain a correlation between the occurrence of 
these natural breakdowns and the occurrence of the storms; but, I think 
it is evident that one would not expect these events to happen at the 
same time, therefore, the storage could be used at least in part to 
catch the mistakes. The problem of the overflows from combined sewers, 


'37 


of course, is one which is attacked directly by this method of pro¬ 
viding storage at the treatment plant. 

The matter of duration of storage is important, because long periods 
of storage would require facilities for keeping the water aerobic. We 
found that the duration of storage is typically a matter of several 
days, which would require aeration. Because of the large fluctuation in 
the depth of water in the storage zone (particularly if it is going to 
be underground storage) we felt that there should be new methods for 
aerating these deep flows. One of the ideas proposed is a floating 
aerator which goes up and down with the water surface which has a 
telescoping draft tube on it so that the entire depth of the flow is 
(or depth of the water stored) affected by the currents produced by the 
floating aerator. The solids that would be deposited in these locations 
would require handling. We envisage separate solids handling facilities 
and separate pumps to receive the material from a bottom scraping mech¬ 
anism. 

This concept is basically a very simple one. It has not been applied 
to sewage treatment plants in the past, I believe, largely because 
there was no economic incentive to do so. The economic and performance 
factors are changing; we are spending a great deal more per million 
gallons per day capacity now as we get into more and more advanced forms 
of treatment. The rules of the game have also changed, and now we’re 
talking not about what our average percent removal is, but we're talk¬ 
ing about the impacts on the receiving stream--whether those impacts 
are of short duration or of long duration. 

I believe that we are going to be seeing more and more of the applica¬ 
tion of this storage function to the treatment system and I think it 
will be found in two locations—in the treatment plant, and (in the 
case of long transportation systems) out at the end of the line in 
order to give higher percent utilization of the sewer itself. This 
type of design can very well be incorporated in new plants and old 
sewers in order to gain higher utilization of those existing facilities. 

QUESTION: Would you reduce the size of the lateral sewers because you 
reduce the size of the treatment capacity? 

BAUER; I would talk about two flow rates; one would be the flow rate 
at which you would move water away from the places where it 
originated to the treatment plant, and the other would be the 
flow rate through the treatment plant itself. You could have 
a high flow rate to the storage, and a lower flow rate from 
the storage to the treatment. Now, if I understand your ques 
ti.on—your saying: why don't you store it out in the neighbor 
hoods? Yes—and, if you did put the storage out there you 
would gain a twofold benefit: you would not only reduce your 
treatment plant capacity, but you would reduce your transpor¬ 
tation cost. The only limitation that I can see to that is 


38 





QUESTION: 

BAUER: 


QUESTION: 

BAUER: 

QUESTION: 

BAUER: 

QUESTION: 

BAUER: 


the practical limitation of size, because, if you are going 
to have a good storage facility it has to be large enough to 
have the solids handling and the aeration facilities with it, 
and warrant some kind of attention by personnel so that you 
do not want them all over the place, but at some strategic 
location. I believe it would be very practical to do this 
in a large system. 

What is the storage volume of the sewers themselves? 

That is a very important factor. I know that in the City of 
Detroit this has been one of their considerations for a long 
time in sizing a sewer; to evaluate its effect on the treat¬ 
ment capacity. The Racine Avenue Pumping Station (in Chicago) 
has very large sewers coming to it and, as I recall, they 
amount to something like a quarter of an inch or so, a fairly 
substantial amount of storage, maybe a quarter of an inch 
spread over the watershed. The minimum that we are thinking 
about for the Deep Tunnel plan I believe is 1 in.; so, you 
see that existing storage in some of these large interceptors 
can be a very substantial fraction of that. In the design 
of the system that certainly has to be taken into account. 

I am talking storage, in addition to the storage that you 
would have anyway, because of the volume of the system. 

What are the costs of pumping the water to the surface? 

Those costs were included in the cost of storage; we cap¬ 
italized those costs. I think we took the annual cost and 
multiplied by 15 in order to get the equivalent capital cost. 
As I say, the $1.50 included an allowance for the pumping 
from the lower elevation. 

What about the $5? 

That $5 figure corresponds to a concrete box constructed 
near the surface and includes a small allowance for pumping. 

What about the effect upon the activated sludge process be¬ 
cause of bringing in the stored sewage? 

We are talking about 1.25 ratio of total flow to average 
flow so that the capacity of the treatment would be 1.25 
times dry weather flow, assuming we had all the storage re¬ 
quired. We would be adding sewage that had already been 
partially treated as it would be aerated down below. There 
would be a drop-off in the BOD. This would mean that some 
of the food for bacteria would have already been used up and 
would not be available for the bacteria that were operating 
in the activated sludge plant. However, it may be that the 


39 


QUESTION: 

BAUER: 

QUESTION: 

BAUER: 


BACON: 


amount of variation in food supply with storage would be less 
than without storage. We have no way of proving that and I 
think it is something that could be studied, it would be very 
interesting. Such a study would actually stimulate the aging 
of the sewage and add it to fresh sewage to see what effect it 
had on treatment. Implicit in my studies to date is the as¬ 
sumption that there would be no fundamental change because of 
the addition of the aged stored sewage. 

Would there be a different strain of bacteria developed in 
the Deep Tunnel and could these be consistently introduced 
into the treatment plant? What would be the effect on the 
treatment process? 

This has not been evaluated so I do not have any way of an¬ 
swering your question. 

Have you related the savings in treatment plant costs for the 
combined sewer area that the Sanitary District serves to this 
figure (figure $600 million to one billion for various ram¬ 
ifications of the Deep Tunnel and Underflow Plan)? 

Yes, we did make an analyses of that. If you did not have 
any storage and you were to design for two times dry weather 
flow, as I recall, the total combined treatment plant capacity 
(for the Chicago Sanitary District) would be 3600 mgd. If 
we were to--by regulating flows through these piants--reduce 
that required capacity to 1.25 times dry weather flow, then 
the saving would be something like 1350 mgd. Now the cost 
of this incremental plant capacity that would not have to be 
constructed, assuming advanced forms of treatment would be 
required, would be say $400,000 times 1350 = $540 million. 

If that is the ballpark figure that we are in, and there is 
a savings of something on the order of $500 million in treat¬ 
ment plant capacity, because of the regulation afforded by 
storage, that becomes a very significant cost factor. It 
was not really emphasized in the work that has been done so 
far; I think partly for the reason that there was no pilot 
plants to demonstrate this effective reduction. On the basis 
of the analyses made here, I am assuming that we do not have 
the kind of effect that Mr. Leary mentioned; but, I think 
that kind of effect has to be evaluated before you could say 
for sure that you could save that much in treatment plant 
capacity. At any rate, it is a large number. 

I think there is something else that should be added here; 
it is not just a matter of cost. In the Chicago area where 
they have gone quite far in a rapid sand filtration of a 
rather crude type and with micro-strainers, it has been 
demonstrated that we can no longer tolerate these wild 


4o 



fluctuations in the secondary effluent ranging from 15 ppm 
BOD and 25 ppm of suspended solids to twice those figures 
and still come off with a consistent tertiary effluent. 

BAUER: I think we found that if we did get into micro-strainers which 

could be an extremely economical type of tertiary treatment, 
they just will not take an inconsistent or double loading 
from a secondary treatment. So, in a sense the high standards 
of 4 ppm of BOD and 5 ppm of suspended solids cannot be 
achieved without storage. You are going to have to go into 
tertiary facilities with something more uniform and, 
therefore, it is not only a matter of cost figures, but a 
matter of consistency of the load application to the tertiary 
facility. I do not see that there is any doubt in the world 
in the Chicago situation that this fact has been demonstrated. 
Consequently, whether you are going to use storage to get a 
more uniform result in flow to the tertiary or whether you 
are going to go back to the primary and secondary and use 
such things as chemical treatment to try to come out of the 
secondary with a more consistent effluent remains to be seen, 
but, it is more than just a matter of cost. 

I neglected to mention that in the Chicago tunnel plan there 
are also some surface storage facilities which are large 
dyked areas for the storage storm water. These have a much 
lower unit cost than I have calculated here and I think if 
it is possible in any area to use an uncovered open earthen 
vessel for the temporary storage that it is so economical as 
to make the storage extremely attractive. I assumed in the 
cost analyses in this report that it would not be possible; 
it would require either a concrete box with a lid on it or 
underground storage. But is is true that the regulation of 
the flows has a great deal of benefit. 


4i 


POLLUT/ OAJ /A/DDX 



DOLLARS PS'P M/LL/OA/ &AILO//S — 


42 
























o o o o 

C \0 \A -3 


o o 

CM 


O O 

H 


C\J 


you ni aos 


^3 


PERCENT OCCURRENCE EQUAL TO OR LESS THAN 















































12 








































































































































Fig. 3 











































































































































STORAGE VOLUME - M.G. 


note: based on analysis 

OF SANITARY DISTRICT 
OF BLOOM TOWNSHIP 
OPERATING RECORDS. 


Fig. 


46 


































































































































Total spillage, 1949-1964 - thousand acre feet 


Total runoff from AT 



47 


Percent of total runoff spilled 













































RATIO TO DRY WEATHER FLOW, Q 0 


' 


RETURN LINE 
FROM STORAGE 




DOMESTIC WASTEWATER VOLUME STORED 
DURING MAXIMUM DAY 


Fig. 6 


1.5 Q 0 


48 


































































Section 4 

THE IMPACT OF THE DEEP TUNNEL PLAN ON 
WATER RESOURCES IN THE CHICAGO AREA 

by 

Victor Koelzer 

Chief, Engineering & Environmental Science 
National Water Commission 
Arlington, Virginia 22203 


49 











THE WATER CONSERVATION ASPECTS OF THE DEEP TUNNEL PLAN 

FOR THE CHICAGO AREA 


SUMMARY 

The Harza-Bauer proposal of a Deep Tunnel Project for the Metropolitan 
Sanitary District of Greater Chicago is designed to provide temporary 
storage for storm water and its accompanying pollution load. Tunnels 
and storage areas would be excavated in solid rock at elevations varying 
from 250 to 800 ft. below ground level. They would hold storm runoff 
which now floods basements and viaducts and pollutes streams in the area. 
On cessation of the storm, the stored water would be pumped to the 
surface and then to the District's treatment plant. After treatment, 
it would be returned to the rivers and streams of the area. 

The attached paper describes the impact of the Deep Tunnel Project on 
two aspects of the water resources of Northeast Illinois - surface 
water and ground water. It shows that the benefits to conservation of 
water could be as significant as those originally expected for flood 
and pollution control. 

For surface water, it is estimated that the Deep Tunnel Project would, 
in effect, ultimately make available an additional 515 cfs (332 mgd) 
for use in the Northeast Illinois, because of better regulation and 
complete treatment of storm water overflows. This compares with about 
1,700 cfs of present pumpage from Lake Michigan for domestic and in¬ 
dustrial use. The value of this water, when fully used , is estimated 
to range from $3.6 million to $6.0 million annually for each 100 cfs 
(65 mgd), depending on alternatives. This would justify a capital 
investment, if staged to meet uses, of $18 million to $86 million, 
depending also on interest rates to be used, for each 100 cfs. 

For ground water, the paper describes elaborate measures planned to - 
protect the aquifers, presently sources of about 130 mgd of the 
metropolitan area supply, from pollution by the Project. It demon¬ 
strates how the Project could serve as a management vehicle to reverse 
the trend of ground water "mining" in the metropolitan area. 

My paper is on the subject of the water conserving aspects of the 
Deep Tunnel Project for Chicago, made possible by the complete 
treatment and controlled releases of storm water overflows. The 
National Water commission, of course, has a very great interest in 
conservation of water--in fact, one of our principal studies is on 
methods of conserving water. 

However, while I, as a member of the Commission's staff, have great 
interest in the Deep Tunnel Project from that viewpoint, I must make it 
clear that this paper stems, not from any studies I have been associated 


51 



with while with the Commission--rather it derives from studies made 
under my supervision while I was with the Harza Engineering Company. 
Most of the information was contained in a 1969 Harza-Bauer report 1 . 
The views expressed hereafter are my own, and not those of the Commis¬ 
sion. 


THE DEEP TUNNEL PROJECT 


The details of alternative proposals for deep tunnels in the Chicago 
area have been described by other participants in this Institute. The 
concepts of water conservation that are presented in this paper are 
those which apply to the Harza-Bauer "Deep Tunnel Plan," as proposed 
to the Sanitary District . Some of the concepts also might apply to 
other plans for deep tunnels--these will be touched on briefly later 
in this paper. 

Although the details of the problem and of the Harza-Bauer plan are 
presented in other papers, a brief discussion is presented here for 
completeness. 

THE PROBLEM 

Nature has treated the Chicago area very poorly in providing for handling 
of storm water and the accompanying pollution load. The flat topo¬ 
graphy and the low gradients on most of the small streams have always 
caused difficulties in drainage. In its natural state, much of the 
Chicago area was a swamp. 

The early sewer systems in the Chicago area were combined sewers, 
intended to handle both storm water and raw sewage. This practice 
has continued, for the most part, until the present. The present 
combined sewer system serves 300 square miles of heavily populated 
area. 

In time of storm, the capacity of the sewer and treatment system is- 
too small to handle both sewage and storm water. Therefore, during 
such periods relief is obtained by discharge of the mixture of storm 
water and raw domestic and industrial sewage to the Illinois Waterway 
system. The overflows from the combined sewer system enter the Waterway 
at some 400 locations, as shown on Figure 1. 


^ "The Impact of the Deep Tunnel Plan on the Water Resources of 
Northeast Illinois," A Report by the Harza Engineering Company 
and Bauer Engineering, Inc., prepared for the Metropolitan 
Sanitary District of Greater Chicago, February 1969. 

2 Ibid. 


52 



When the overflows are too large for the Waterway system to accomodate, 
it is necessary, on rare occasions, to discharge this mixture of storm 
water and sewage to Lake Michigan. Such a discharge occurred on 
August 16, 1968, causing Chicago's beaches to be closed on one of the 
hottest weeks of the year. While such occasions have been rare (only 
four times in the last 25 years), they are detrimental to recreational 
activities of the area. Associated with this, on many occasions, has 
been flood damage along the waterway. 

Locally, the increased runoff which has accompanied urbanization has 
overloaded the small sewer capacity before it can be relieved at their 
overflow points on the Waterway. In suburban areas, capacities of 
local streams which serve as outlets also are limited. Because of 
these limitations, relief occurs locally, both in the city and the 
suburbs, by temporary storage on streets, underpasses, and basements. 
Since this water is frequently polluted, it is a health hazard as 
well as a property damage hazard. 

DESCRIPTION OF THE DEEP TUNNEL PROJECT 

The general concept of the Deep Tunnel Project is relatively simple, 
as shown on Figure 2. It combines certain features of what has become 
known as the "City of Chicago underflow" concept with underground 
storage, treatment, and hydroelectric power generation. Basically, the 
Deep Tunnel Project involves: 

a. Providing lower outlets for existing and proposed new main 
sewers and interceptors, which will increase sewer capacities 
by increasing their hydraulic gradients. 

b. Intercepting, conveying, and storing combined sewer overflows 
that might otherwise overflow to the waterways. 

c. Releasing the stored waters at a reduced rate, first to an 
advanced waste treatment plant and then to the waterway. 

This will virtually eliminate both pollution and flooding in 
the waterways due to storm water overflows. 

Ultimately, the Deep Tunnel System is proposed to service the entire 
area of 300-square miles of combined sewers that are shown on Figure 1. 
The First Construction Zone, as originally proposed, would serve 62 
square miles in the Lake Calumet area. Since the original scheduling, 
a second zone which would serve an area on the North Branch of the 
Chicago River has been planned for concurrent construction with the 
first zone. The proposed system for the entire service area, including 
the Calumet and North Side areas, is shown on Figure 3. The service 
area of the First Zone and a general layout of the project features are 
shown on Figure 4. 

The Deep Tunnel System will start with the capture of storm water 
overflows from combined sewers at a point just upstream of the outfall 
to the waterway. These polluted overflows, instead of entering the 


53 


waterway, will be dropped through vertical shafts into a network of 
smooth tunnels under the waterways, located at two principal levels, 
in the Niagaran and the Galena-Plattevi11e dolomites. The tunnels, 
designed for flow under pressure (to utilize the large head available), 
will conduct the overflow water to a central, mined storage reservoir, 
some 830 feet below the land surface. The mined storage reservoir, 
made up of large, unlined chambers in the Galena dolomite, will consist 
of two sections, a settling chamber and the main storage reservior. 

Water will first flow into a settling chamber, which will be large 
enough to contain runoff from small and medium storms, and retain much 
of the solids loads of large storm runoffs. The partially treated 
water will then flow into the main storage reservior, from where it will 
be pumped through reversible pump-turbines to a diked reservoir on 
the surface, using off-peak power. Storm water stored in the surface 
reservoir will further improve in quality due to sedimentation and 
oxidation, and will then be fully treated and released gradually to 
the waterways. In this process, the Deep Tunnel System will eliminate 
99.5 percent of the pollution load presently reaching the waterways 
through storm overflows from the sewers. 

Both the surface and lower reservoirs will serve the dual function of 
storm water retention and storage for hydroelectric power generation. 
These uses are compatible. Analyses based on 96 years of rainfall 
records indicate that hydroelectric generation would be curtailed less 
than 0.1 percent of its operating time due to storm water retention. 

TYPES OF IMPACTS ON WATER RESOURCES 

Although the Deep Tunnel Project was conceived initially as a flood 
control and pollution control project (with incidental power generation 
facilities), it has an impact on the water resources of the area of 
considerable importance. In the future, as the Chicago area becomes 
increasingly in need of more water, this impact could emerge as being 
fully as significant as the "primary" purposes of flood and pollution 
control. 

There are two ways in which the Deep Tunnel Project would have an 
impact on the water resources of Northeast Illinois. The first is in 
conservation of surface water resources, the second is in management of 
ground water resources. Each will be dealt with separately in the 
following sections. 

IMPACT ON THE SURFACE WATER SUPPLY 
THE PRESENT SUPPLY 

The surface water presently available to the Northeast Illinois area 
consists primarily of the supply from Lake Michigan. Prior to 1967, 
there was no limitation on the amount of domestic and industrial 
pumpage from Lake Michigan by the City of Chicago and a privileged 
few of its suburbs. However, the 1967 decree of the U.S. Supreme 


54 


Court has made the surface water supply much more critical, by intro¬ 
ducing new limitations. While the amount of water that could be pumped 
from the Lake would be unlimited if it were possible to return the used 
water to the Lake, such return is considered unacceptable under present 
conditions because of potential pollution of the Lake. Under present 
conditions, the only acceptable procedure is to direct the water, after 
it is used, down the Illinois Waterway. 

The amount of diversion from the Lake to the Waterway is now limited by 
the 1967 decree to a total of 3200 cfs (2,060 mgd). The decree defines 
three components that must be counted in such diversion. These 
components are as follows: 

a. Domestic pumpage (including water supplied to commercial 
and industrial establishments but excluding well pumpage), 
the sewage effluent derived from which is not returned to 
Lake Michigan. This component has been estimated to 
average 1,734 cfs (1,110 mgd) during the 1950-1964 period. 

b. Storm runoff which, without the interception by the canal 
system of the Metropolitan Sanitary District, would have 
entered Lake Michigan from the natural drainage of the Lake 
Michigan watershed. This component has been estimated to 
average 550 cfs (355 mgd) during the 1950-1959 period. 

This was prior to construction of the O'Brien Lock, when the 
area intercepted in this manner was about 450 square miles. 

The Sanitary District feels that the Special Masters' 
estimates are high--that the correct figure is more in the order 
of 400 cfs. The District feels that the 550 cfs is more 
applicable to current conditions, with O'Brien Lock, where 
the area of normal Lake Michigan drainage that is intercept¬ 
ed is about 740 square miles. 

c. Direct diversion from the Lake into the canal system of 
the Sanitary District, estimated to average about 945 cfs 
for the 1950-1964 period. (Since the total of the three 
components has historically been 3,229 cfs, it can be 
presumed that this component would have to be reduced by 
29 cfs, to 916 cfs, to comply with the decree.) 

The total amount of water to be diverted from Lake Michigan (3,200 cfs) 
presently serves the purposes of (1) municipal and industrial water 
supply, (2) maintaining sanitary conditions in the Illinois Waterway, 
and (3) navigation. The 1967 decree of the Supreme Court specifies that 
the State of Illinois may apportion the 3,200 cfs among these uses as 
it sees fit, subject only to any regulations imposed by Congress in 
the interest of navigation or pollution control. Thus, the 1,734 cfs of 

3 Report of Albert B. Maris," Special Master, to Supreme Court of the 
United States, Wisconsin et al, vs Illinois et al, Dec. 8, 1966, p. 87. 

4 Ibid., p. 87. 

5 Ibid., p. 87. 


55 



"domestic pumpage" can be increased if the needs of navigation and 
pollution control are adequately cared for with their reduced supply. 

In addition to surface water diverted from Lake Michigan, there is an 
undeveloped source of water in streams naturally draining away from 
Lake Michigan. This supply is quite erratic in its occurrence, and 
would require substantial storage facilities for regulation. Major 
streams which might be utilized in this manner include the Des Plaines, 
the Fox, and the Kankakee. Reliable cost estimates are not available 
for the storage and transmission systems that would be required, but 
they undoubtedly would be very expensive. 

Another method of utilizing the above rivers, proposed by the Lake 
States which opposed Illinois in the suit before the U.S. Supreme 
Court, would be to divert water into Lake Michigan from the rivers to 
compensate for water diverted from Lake Michigan. The cost estimates 
by the Lake States are believed by Illinois to be quite low and the 
feasibility of making compensating diversions from the three basins, 
of the magnitude suggested, are open to serious questions. 

THE NEED FOR WATER MANAGEMENT 

The 1967 decree of the Supreme Court provides that application for 
modification of its terms can be made only if the State of Illinois 
demonstrates (a) that the ground and surface water resources of the 
region are not adequate to meet the needs, and (b) that all feasible 
means that are reasonably available have been employed to conserve 
and manage the water resources of the area. 

The terms of the 1967 Supreme Court decree are very positive in stating 
what Illinois must do if it ever wishes to obtain more than 3,200 cfs 
from Lake Michigan. Mr. W. C. Ackermann has been very active in pointing 
this out. He has stated: 

It is perfectly clear, however, that the State of Illinois has 
the duty so to manage its water resources and regulate the use of 
the water now available to it as to conserve this essential commo¬ 
dity to the utmost practicable extent for the use of its people. 

This surely means that the State must definitely undertake the 
task of managing its water resources, at least in its Northeastern 
Metropolitan Region, on a broad regional basis in the most modern 
scientific manner and that all feasible methods for developing the 
supply and conserving the use of domestic water which are reason¬ 
ably available to it should be employed, before the State receives 
authority to divert more than the present 3,200 cfs from Lake 
Michigan . b 


6 "Implications of the Maris Report," W. C. Ackermann, Chief Illinois 
State Water Survey, A talk prepared for the Great Lakes Water Resources 
Conference in Toronto, Canada, June 25, 1968. 


56 



CONSERVATION OF STORM RUNOFF FROM DES PLAINES WATERSHED 


In addition to the ?• rmwater overflows in the Lake Michigan natural 
watershed, signific overflows that occur in Des Plaines River 
watersheds will be tured by the Deep Tunnel Project and treated. 

These overflows ar< *om an estimated 60 scnare miles of the 300 
square mile combine, sewer . . . T,\ over ows are estimated to be 
the same as from the Lake Michigan wafers!' on a cfs-per-square-mi 1 e 
basis, and thus would be about an average of 50 cfs (32 mgd). 

Since the origin of this water is from outside the Lake Michigan 
watershed, it is not charged against Illinois' diversions from that 
watershed. In fact, since it would ultimately be discharged into 
Lake Michigan, or accomplish the equivalent thereof, it would be an 
import into the basin, to serve as a credit against diverted water. 

The Sanitary District has recently adopted resolutions which eventually 
could lead to providing flood control storage on a number of small 
streams, outside the combined serviced area, which enter the Waterway. 
These streams, which drain approximately 1,260 square miles, would be 
controlled in a manner that would require releases to be made in a 
matter of a relatively few hours, or days at most, after a storm. 

Thus their releases could not be used directly as a supply of water. 

It seems possible, however, that as the Northeast Illinois area 
becomes more restricted by the limits of the decree in relation to - 
growing water needs, some coordinated operation of the Deep Tunnel 
system and such flood control reservoirs could be accomplished. 

Flood releases from these reservoirs might be made directly to the 
Deep Tunnel system for all except the major storms, in effect creating 
additional imports to the Lake Michigan watershed. Such coordination 
of operation probably could be made feasible, without any loss of 
dependable power capacity, because it could be done at a time in the 
future when the power load curve is such that the number of kilowatt- 
hours of energy (equivalent to the water storage volume usable for 
power) would be significantly less than initially. 

CONSERVATION OF PRESENT DIRECT DIVERSIONS TO THE WATERWAY 

The water diverted directly to the waterway system (estimated to average 
945 cfs, but assumed to be decreased to 916 cfs to comply with the 
decree) is used for navigation and maintenance of sanitary conditions. 
Although the Corps of Engineers has not stated what it considers to be 
the minimum amount necessary for navigation, it has stated that the 
total present diversions would be adequate to meet future navigation 
requirements, with the improvements it contemplates for the future. 

The Deep Tunnel Project will give complete treatment to storm water 
overflows, which have contributed heavily to unsanitary conditions in 
the waterway. The Sanitary District also has programs aimed at 


57 


eliminating the adverse effects of the other two main sources of 
waterway pollution (sewage plant effluent and industrial wastes). 

The present sewage plant effluents are expected to be given advanced 
waste treatment processes. The industrial waste pollution is being 
eliminated by measures taken by industry, under the legal requirements 
of the recently adopted waterway standards being enforced by the District. 

After these steps are taken, there will no longer be a need for 
diversions to maintain sanitary conditions. There will remain a need 
for direct diversions to serve navigation, since water will be needed 
for lockages at the mouth of the Chicago River and at the O'Brien Lock 
on the Calumet River. There will also be leakage through these 
locks. The combined amounts of water needed for such lockage and 
leakage at the mouth of the Chicago River and at the O'Brien Lock has 
been estimated as being 130 cfs'. The Sanitary District has estimated 
the requirements for lockage and leakage at Wilmette to be 20 cfs. 

Thus, the total lockage and leakage requirements would be about 150 cfs 
(100 mgd). 

It probably would be possible to conserve most of the lockage and leakage. 
However, as a minimum, there would be in the order of 765 cfs (the 916 
cfs of direct diversions diverted minus 150 cfs) which could be added 
to the region's usable water resources if all three sources of pollution 
were eliminated. The Deep Tunnel Project cannot claim credit for all 
of these savings, since other measures are also necessary. However, 
it could, on the basis of percentage of pollution eliminated, claim 
credit for conservation of about one-third, or 255 cfs (165 mgd). 

EFFECTS ON NAVIGATION DOWNSTREAM 

The 210 cfs of storm water runoff in the Lake Michigan watershed, plus 
the 50 cfs originating outside the watershed, if converted to a usable 
water supply, would eventually return to the Illinois Waterway and would 
be uniform in flow, rather than occurring erratically in storm periods, 
as at present. This would benefit navigation significantly. The 765 
cfs of direct diversions that is saved, if used as municipal and in¬ 
dustrial water supply, also would return to the waterways. Thus the 
total average water available at Lockport and downstream locations 
would be same as at present, but would be better regulated and vastly 
improved in quality. 

SUMMARY OF EFFECT ON SURFACE WATER SUPPLY 

On the basis of the above estimates, the Deep Tunnel Project would make 
available the following additional quantities of water for municipal and 
industrial use: 

From the storm water originating 

within the Lake Michigan watershed 210 cfs 135 mgd 


7 


Maris Report, p. 86. 


58 




From storm water originating out¬ 
side the Lake Michigan watershed 50 cfs 32 mgd 

Savings in present direct 

diversions 255 cfs 165 mgd 

TOTAL 515 cfs 332 mgd 

This increase in usable water supply from the existing water resources 
of Northeast Illinois is more than one-half the 930 cfs of additional 
water needed to serve the growth in population in the Metropolitan 
area bv the year 2000, as estimated in the report by the Special 
Master^. 

STAGING OF USE OF ADDITIONAL WATER 

The water conserving potential of the Deep Tunnel Project is ideally 
suited to staging of use of the water, as the needs of the Chicago 
Metropolitan area grow. 

The plan outlined herein is based on the Harza-Bauer plan of 1968. 

Since that time, it is understood that agreement has been reached to 
proceed with an "underflow" concept for an area of the North Shore 
channel, from approximately the junction of the North Branch of Chicago 
River to the Wilmette inlet.' While this will have less storage (about 
1.25 inches as compared to the 2.2 inches provided in the Deep Tunnel 
Project), it will capture a significant percentage of the overflows. 
Since the captured overflows will be given additional treatment, their’ 
release to the waterway will contribute to the cleanup program. 

The first stage of conservation through the Deep Tunnel system might 
be the substitution of the storm water releases that are treated in 
the North Shore channel phase for an equal amount of direct diversions, 
presumably on the basis that equivalent sanitary conditions would 
obtain. The writer does not have specific knowledge of the area to be 
served by the North Shore channel phase, but it could provide a saving 
of 10 to 15 cfs (6 to 1 0 mgd), sufficient for a population of about 
70,000 to 100,000 (at a usage rate of 100 gallons per capita per day, 
which is higher than the present usage in most Chicago suburban areas). 

The next step could be upon the completion of the initial storage for 
the Deep Tunnel Project, under the mined storage concept conceived in 
the Harza-Bauer Plan. This could either be in the Calumet area or in 
the McCook area (see Figure 3), either of which seems to be feasible 
extensions of the underflow phase for the North Shore channel area. 

At that time the additional water salvaged, approximately 40 cfs (25 
mgd) if the First Zone of Figure 4 is developed; could be made 
available immediately by releasing it directly to the waterway as a 
replacement for an equal amount of direct diversion. Since it would be 


^ Maris Report, p. 102. 


59 





fully treated, the 40 cfs that would be saved could be used 
for municipal and industrial purposes. 

I 

Ultimately, when the Deep Tunnel Project is completed, the 260 cfs 
(168 mgd) of storm water runoff that would be salvaged could be put to 
use in the same way. This amount would be sufficient to support an 
additional 1,700,000 persons (at 100 gallons per capita per day). 

The next step after use of the 260 cfs would be to utilize all of the 
savings in direct diversion that can be used without installing addition¬ 
al transmission facilities. The 260 cfs of captured storm water will 
not be released uniformly to the waterway throughout the year—our 
studies indicate this would vary from zero to a maximum of 562 cfs. 

The direct diversions would be increased or decreased as necessary to 
compensate for the changes in rate of release of treated storm flows. 

Any direct diversions that may be saved as a result of complete 
treatment of all sources of pollution (storm water overflows, waste 
treatment plant effluents, and industrial wastes) would be staged 
after the preceding stages are utilized. 

Additional future steps could involve conveyance of all the captured 
storm water back to the lake for regulation to uniform flow throughout 
the year, or capture of additional storm water from reservoir releases 
in areas outside the combined sewer area. Thus the Deep Tunnel Project 
fits in ideally to a staged development of providing additional water 
supply, as the population of the area grows. 

VALUE OF WATER CONSERVED 

The value of the resource that would be conserved is dependent on the 
alternative cost of water supply that might be available. This has not 
been determined reliably for the Chicago area, but several yardsticks 
might be used as the basis for an appraisal. These are: 

a. The average cost of water delivered to all communities in the 
U.S. (including transmission but not distribution costs), 
estimated to be 12 cents per 1,000 gallons. 

b. The anticipated cost of the necessary steps in advanced 
waste treatment (over the cost of secondary treatment) to 
provide water suitable for reuse for municipal and industrial 
purposes, which is estimated to be about 25 cents per 1,000 
gallons (excluding transmission and distribution).9 

c. The cost of providing water to suburban areas (including 
treatment), by pumping from ground water, estimated to be 
15 to 25 cents per 1,000 gallons. 


9 From information in draft of report on this subject by National Water 
Commission. 


60 



In addition to the above, the Lake States estimated the costs for water 
diverted to Lake Michigan from the Fox, Des Plaines, and Kankakee Rivers, 
to be 2-1/2 to 6 cents per 1,000 gallons, not including treatment. As 
indicated previously, these estimates are believed to be quite low and, 
therefore, have not been used in the subsequent analysis. 

The justifiable capital expenditures for measures to provide the 
additional water (assuming it were immediately useful upon completion 
of the facilities) would also depend on the terms of amortization of 
the facilities (primarily on the interest rate assumed) and the allo¬ 
cation of operating costs to the Water conservation purpose. For 
purposes of illustration, the justifiable capital costs are presented 
in the following table on the basis of annual charges (debt service 
plus operating costs) of 7, 10, and 12 percent. 


TABLE # 


Value of Conserving each 100 cfs (65 mgd) 


Alternative Costs Annual Value Justified Capital Expenditure 
(Cents per (millions of for various annual charges 


Source _ 1,000 gal.) dollars) (in millions of dollars) 





7% 

10% 

12% 

Average in U.S. 
From Advanced 

12 

2.1 

30 

21 

18 

Treatment 

25 

6.0 

86 

60 

50 

Present Cost to 






Suburbs 

15-25 

3.6-6.0 

51-86 

36-60 

20-50 


It must be recognized that the above values are attainable only when 
there is a definite market use for the water, at the prices indicated. 

Such uses will build up only gradually, over a period of years—hence 
the values are shown for 100 cfs increments, to avoid the inference that 
the complete capital expenditure to provide a total saving of 515 cfs 
(332 mgd) is immediately justified. It will be necessary to make a 
reliable appraisal of the buildup in uses and the resulting cash flow, to 
develop a dependable basis for the justifiable staging of capital expenditures 


IMPACT ON THE GROUND WATER SUPPLY 


EXISTING RESOURCES AND USE 

The principal aquifers supplying the metropolitan area are, in order of 
depth, the sand and gravel deposits of the Glacial Drift, the Silurian 
dolomites limestone, the Cambrian-Ordovician sandstones and dolomites, 
and the Mt. Simon sandstone. A description of these systems is given 
on Figure 5. 

In 1967, total ground water pumpage in an eight-county area of Northeast 


61 









Illinois was 243.7 °. Of these, 29.5 mgd came from sand and gravel 
wells, 84.3 mgd from shallow dolomite (Silurian) wells and 129.9 mgd 
from deep sandstone wells. It is estimated that of the 129.9 mgd 
pumped from deep wells, 74 mgd came from the Cambrian-Ordovician 
aquifer and 55.9 mgd from the Silurian and Mt. Simon aquifers, through 
wells which are also open to these two aquifers. 

Over 175 municipalities obtained their supply from ground water in 
1967, using a total of 148.5 mgd. The remainder of ground water usage 
was by industries, 61.8 mgd, and by irrigation and domestic users, 

33.4 mgd. 

The Silurian system has been estimated by the Northeast Illinois Planning 
Commission to have a supply considerably in excess of present pumping 
requirements. However, this system is quite erratic in the occurrence 
of ground water at specific locations, especially within the metro¬ 
politan area, so that there is considerable risk of dry holes when 
wells are drilled. For this reason, the Silurian aquifer is only 
partially used. 

Contrasted with this, the Cambrian-Ordovician aquifer is highly 
dependable as a source and also has a lower hardness. A village or 
industry can be assured of a good yield when it makes the investment 
necessary to drill a well. This aquifer system, therefore, is the most 
widely used and pumpage from this system has increased from about 25 mgd 
in 1940 to 74 mgd in 1967. Major centers of heavy pumping are at 
Des Plaines, Elmhurst and Summit. Because of this heavy usage, the 
withdrawals of ground water from the Cambrian-Ordovician system have 
exceeded the supply available through natural recharge, by some 60 
percent. As a result, water levels have declined from artesian flow 
in 1864 to depths of 650 ft. in 1966. The rate of decline of the 
ground water level, averaging about 13 feet per year over the area, 
is indicative of the difficulties which the area will encounter if 
the "mining" of ground water continues. A water level map for the 
area is shown on Figure 6. 

PROTECTION OF THE GROUND WATER RESOURCE 

The tunnels and mined storage area of the Deep Tunnel System would be 
excavated in the two dolomite rock formations underlying the area 
(Niagaran and Galena-Plattevi11e), at approximately 250 and 800 foot 
depths below the ground surface. The tunnels would be in these'two 
separated rock units, which are part of two completely separate ground 
water systems, while the mined storage area would be only in the lower 
aquifer. The proposed Deep Tunnel System includes elements which have 
been designed to protect these aquifers from any deleterious effects 
of the storm water runoff that would be conveyed in the tunnels and 
stored in the mined area. 


Personal communication, R.T. Sasman, 
to Harza Engineering Company. 


Illinois State Water Survey, 


62 



The principle on which the protection is based is extremely simple- 
even though the implementation of that principle is somewhat complicated. 
The principle is simply that water will not flow "uphill," that is, 
against a positive pressure. The principle is demonstrated in Figure 7. 
It will be implemented by assuring that the water pressure in the ground 
water surrounding the tunnels and mined area will always be greater 
than the pressure inside the tunnels and mined area. If this is the 
case, any flow of water that occurs must be inward, toward the tunnels, 
not outward. Under such conditions, pollution of the aquifer cannot 
occur. 

The protective system that has been devised has been based on extensive 
ground water investigations, including an electric analog computer and 
field drilling, seismic surveys, well logging and pump tests, all of 
which were obtained at a cost of about $2,000,000. 

The upper level tunnel system in the Harza-Bauer plan would be below the 
water level in the upper aquifer system. The tunnels would not be 
allowed to become pressurized above the outside ground water pressure. 

The upper aquifer is used only slightly, and, as a result, the supply 
of ground water available from infiltration of precipitation on the 
land surface, i.e., natural recharge, .is much larger than present 
pumpage from this aquifer. It is also anticipated that future pumpage 
from this aquifer would not exceed the natural recharge. Therefore, 
the ground water pressure in the upper aquifer system would remain 
greater than the pressure in the tunnels, and pollution of the aquifer 
cannot occur, as shown on Figure 7(A). 

Protection of the lower, completely separate, aquifer would require 
slightly different measures. The ground water in this aquifer is 
presently above the elevation of the lower tunnels and the mined 
storage area; however, as indicated previously, because of heavy usage, 
the ground water level is gradually falling, at an average rate of 
about 13 feet per year throughout the area. To adequately protect the 
lower aquifer, this trend must be reversed so that the piezometric ' 
level of the ground water will always be above the level in the tunnels 
and the mined storage area. The principle of protection for the lower 
aquifer is demonstrated on Figures 7(B) and 7(C). 

Two measures are possible to maintain the pressure in the ground water 
above that in the tunnel and mined area. These are (1) artificial 
recharge of the aquifer, and (2) control of ground water pumping. 

A recharge system is entirely feasible, would use relatively small 
quantities of surface water for recharge, and would not necessitate the 
exchange of a surface water supply for a ground water supply with present 
users. Most of the recharge water would move toward existing wells, 
thus augmenting the available supply. The validity of the recharge 
approach has been demonstrated by studies which included a $487,000 
ground water drilling and testing program, construction of an electric 
analog computer, and office evaluation of collected data and analog 


63 


results. Additional subsurface information, obtained through the 
geologic investigations of the area, included a $437,000 diamond core 
drilling program, and a $1,006,000 seismic exploration and geophysical 
well logging program. The results of all these field investigations 
were incorporated into the ground water studies. 

The second method of protection, which may ultimately prove to be highly 
practical, would be to manage ground water pumping in the area in such 
a manner that ground water levels will be maintained at a high enough 
level to assure that the water level outside the storage area is higher 
than inside. This would require substitution of a surface water source 
of supply to a portion of the users now pumping ground water. As ex¬ 
plained previously, it is believed that the Deep Tunnel Project would 
ultimately make a large amount of additional surface water available, 
so that this method would be highly promising and entirely practicable, 
from an engineering viewpoint. A number of complex administrative 
arrangements would be necessary to implement this approach. In effect, 
this would require overall, centralized management of all of the water 
resources of the Northeast Illinois area. Such management arrangements 
would be complicated, but would produce significant overall benefits. 

COORDINATION WITH STATE OFFICIALS 

Throughout the course of the studies underlying the Harza-Bauer Plan, 

Mr. William C. Ackermann, Chief of the Illinois State Water Survey, 
and Mr. Clarence W. Klassen, Chief Sanitary Engineer of the State 
Department of Public Health and Technical Secretary of the State 
Sanitary Water Board, were kept informed on the planned aquifer pro¬ 
tection method and on the progress of the studies. 

Mr. Ackermann commented favorably on the report with respect to both 
ground water and surface water aspects and was particularly interested 
in the possibilities of the Deep Tunnel Project as a key vehicle for 
regional ground water management. He saidll: 

"Your proposed design of recharge and observation wells to main¬ 
tain a positive pressure over the tunnels appears reasonable. Of 
course, we all recognize that a rigorous program of surveillance 
will be required, and if local conditions vary from expectations 
it is conceivable that a few additional recharge wells or in¬ 
creased recharge rates may become necessary. 

We visualize that two general plans of management could be develop¬ 
ed. One would be a regional one in which a special water district 
would assume control over all groundwater pumpage, and could thus 
control water levels over a wide area. Such enabling State laws 


11 Letter of February 12, 1969, from W.C. Ackermann, Illinois 
State Water Survey, to V.A. Koelzer, Harza Engineering Company. 


64 



exist, and we would consider this a desirable, and perhaps eventual¬ 
ly, an essential system. The other plan of management, which you 
outline, is to maintain pressures locally through recharge in the 
vicinity of your proposed works. 

The Deep Tunnel, if undertaken primarily for flood and pollution 
control, will contribute very significantly to the objective of 
demonstrating that Illinois is taking all feasible and reasonably 
available means of conserving water. The completion of the Deep 
Tunnel Project would be the best protection the users of ground- 
water could have that their groundwater resource will be preserved, 
because the control of groundwater levels in the areas of the Deep 
Tunnel facilities which must accompany that Project will fit in 
admirably with a management program for conservation of the ground- 
water resource." 

The contacts with the State Board of Health and State Sanitary Water 
Board were primarily in connection with ground water protection. While 
specific written comments of individuals in these agencies were not 
requested, they raised no questions regarding the adequacy of the pro¬ 
tective system that has been proposed. 


QUESTION: Would you need a new distribution system to effect the re¬ 
charge? 

KOELZER: For the first construction zone, which was about 1/6 of the 

area, the plan was to have 15 recharge wells. The studies 
indicated these wells would be adequate to maintain the 
levels. 

In view of the fact that the first portion of storm water 
contains the highest percentage of the solids, was considera¬ 
tion given to capturing only a first portion of the overflow 
rather than the total? 

KOELZER: This was not done initially for the Deep Tunnel Plan as 

presented to the Sanitary District, because it was believed 
that the water quality standards could not be met by capturing 
only the first flash. This was a criticism that was raised, 
but information was not then available as to the cost. 


QUESTION: 


65 




(• u 



LAKE 

MICHIGAN 


*. - . 


o *. * 


Lake 

Calumet 


C - 

CHICAGO DEEP TUNNEL SYSTEM L * •> 

| 

FIRST CONSTRUCTION ZONE 

! • l\ 

COMBINED SEWER OVERFLOW POINTS 


, VJ br rL'.r < 



HARZA ENGINEERING COMPANY DWG NO. 387B 
BAUER ENGINEERING INC 


66 


\ 


Fig- l 













CHICAGO DEEP TUNNEL SYSTEM 

THE DEEP TUNNEL 
CONCEPT 


HARZ A ENOINEERINO COMPANY 0V»0 NO. 897 0 
BAUER ENGINEERING INC. 


67 


Fig. 2j 





































































































































































OE AREA 


'NTRAL AREA 


MICHIGAN 


RACINE AREA 



Scale | 0 I ? 3 4 Miles 

brr-tr.Lj-d- k r jaJ - 1 


GREATER CHICAGO 

POLUTION AND FLOOD CONTROL SYSTEM 


'• Mom conveyance tunnel 
*» Moin Sewers (tunnel or conventional) 


GENERAL MAP 















BAUER ENGINEERING INC. 

HARZA ENGINEERING COMPANY DWG. NO. 387B 201 


70 



























• 5 



A 

X 


LEGEND: 

Conveyance tunnels in the Niagaran dolomite 

Conveyance tunnels In the Galena and Platteville dolomite 

Drop shaft and shaft number 

Project drainage area 

Recharge metis 

Monitor wells 


Scole 1000 0 3000 Feet 


71 


CHICAGOLAND DEEP TUNNEL SYSTEM 
FIRST CONSTRUCTION ZONE 


GENERAL PLAN 


LLL 



















AQUIFER 

STRATA 

AVERAGE 

THICKNESS 
(feet ) 

PREDOMINANT 

ROCK TYPE 

WATER-YIELDING PROPERTIES 

GLACIAL 

DRIFT 

Pleistocene 

65 

Till, lenses 
of sand & 
grave 1 

Not tested. Significant deposi 
highly productive sands S grave 
not encountered. 

t s of 

Is were 

SILURIAN 

Niogaran 

and 

Alexandrian 

4 00 

Do 1om i t i c 

1 ime s t on e 

Very small yields of water from crevices 
and solution channels. Yields range 
from less than 0.1 to 1.0 gpm per foot 
of d rawd own . 


Moquoketo 

170 

Shale 

Not water yielding, acts as barrier 
between Silurian & Cambrian-0rdovic i an 
aquifers. 


Galena- 

Platteviile 

330 

Dolomite 

Least permeable unit ot the 

Cambrian - 0rdovician aquifer. 
Yields very small amounts of 
water from crevices, ranging 
from less than 0.1 to l.l gpm 
per foot of drawdown. 


region. 

for 

i es . 

z 






CD — 

•C k. Q. 

<4 

o 

> 

o 

o 

Glenwood - 

St. Peter 

90 

Sandstone 

Yields small amounts of water 


■*“' (D Q- 

ZD 

C (t3 (A 

— 2 

*4— <0 

CAMBRIAN - OR 

Prairie Du 

Chien, 

Eminence 

and 

Potosi 

340 

Dolomite 

Locally well creviced 
central portion of this unit 
responsible for high yields. 


'Oductive aquife 
large amounts c 
ial and industri 


Franconia 

130 

Sandstone 

Yields moderate amounts of 
water. 


o. 

•o CJ 

— — 

V) <u c 

O ... 3 


Ironton- 

Galesville 

170 

Sandstone 

Most dependable and most 
productive unit of the 
Cambrian-Ordovician aquifer. 




Eau Claire 

Not 

penetrated 

Shale 

Not water yielding, acts as b< 

between Cambrian-Ordovician a 
Mt. Simon aquifers. 

i r 

i d 

r i e r 

MT SIMON 

Mt. Simon 

Not 

penetrated 

Sandstone 

Not tested. Reported to yield 
amounts of water. 

mode rate 


NOTE: Water-yielding properties and 
thickness based on exploration 

program in First Construction CHICAGO DEEP TUNNEL SYSTEM 

Zone; may be different in other FIRST CONSTRUCTION ZONE 

areas. 

77 REGIONAL AQUIFER SYSTEMS 

Fig. 5 




























AQUIFERS IN DEEP 
TUNNEL ZONE 


73 


R 6 E R 8 E R 10 E R'2E 



NOTES: 

/. The piezometric surface represents the water pressu 
Aquifer, i.e. the level to which water will rise in a wt 

2. Drawings based on Illinois State Water Survey; Sos, 

74 

BAUER ENGINEERING INC. 

HARZA ENGINEERING COMPANY DWG. NO. 387B APRIL I960 






























































R 12 E 


R 6 E R 8 E R 10 E 



Scale 0 5 10 Miles 

Li-J—I_I—I L.l.ilJ 

f level m the confined Cambrian -Ordovician chicagoland deep tunnel system 

/ penetrating the artesian aqifer. FIRST CONSTRUCTION zone 

'tan, McDonald and Randall ,196 7 




75 


CAMBR1AN-0RD0V1C1AN AQUIFER 
WATER LEVEL WAPS 


















































































(A) 





iWatero table 


Water level in well shows artesian 
pressure in Galena-Plotteville — 


Artesian pressure in Galena~Plotteville to be 
maintained at thi s leve l by recha rge—^ 


Excess ground-water- 
,/pressure outside / 


( Max. water level tunnels 


tlin fd mi ned/storoge tunnels / 


5SERVOIR 


o-i 


- 200 - 


? I -400- 

o 


.2 


'6 -600- 


Glaclal 

Drift 


Niogoran 

Dolomite 


Alexandrian 

Dolomite 


MoquoXeta 

Shale 


-aoo- 


Golena- 

Plattevllle 

Dolomite 


BAUER ENGINEERING INC. 

HARZA ENGINEERING COMPANY DWG. NO. 387X13 


76 


















































































































































































































Water level in well shows artesian 
pressure m Galena*Platteville ^ 


Water level in hypothetical pipes 
shows pressure in tunnels — 


Water table 


Galena "PlatteviUa to be— 


Artesian pressure-in 

maintained-_aOhis -level by -recharge 


' Excess'ground "water 

pressure outside •_— 

rthe-turmels— “'V' 


Pressure level in tunnel 
-dunhg maximum storm 


7 CONVEYANCE ..TUNNEL: 

LENA^RLATTEyjL 


. i 


EXPLANATION' 

Arrow indicates direction of water pressure. 


t 

i 


CHICAGOLAND DEEP TUNNEL SYSTEM 
FIRST CONSTRUCTION ZONE 

PRINCIPLE 

OF AQUIFER PROTECTION 


77 





















































































































































Section 5 

THE POTENTIAL OF PUMPED STORAGE FOR HYDROELECTRIC GENERATION 
IN MULTI-LEVEL DEEP TUNNEL SYSTEMS 

by 

Kenneth E. Sorenson 
Vice-President 
Harza Engineering Company 
400 West Madison Street 
Chicago, Illinois 60606 


























MULTIPLE USE OF UNDERGROUND RESERVOIRS 
FOR POWER GENERATION 


USES OF RESERVOIRS 

Large underground chambers excavated for urban flood control would 
have relatively infrequent use, and would very rarely be fully used 
as single-purpose reservoirs. One possible dual function could be 
for hydroelectric pumped-storage. Another multi-purpose function 
could be the circulation of condenser water for underground nuclear 
generating plants. 

This paper describes briefly the possibilities and implications of 
such multi-purpose uses. 


PROBLEMS OF THE POWER INDUSTRY 

From the viewpoint of transmission and reliability, generation is 
preferred close to the major urban centers. Obtaining publicly 
acceptable routes for high voltage lines from more distrant plants 
is becoming increasingly difficult. 

In the case of pumped-storage, many large urban areas do not have 
favorable topography for conventional hill-top reservoirs. And yet, 
the functions of such plants for day time peaking and system reserves 
are best served if close to the load centers. Even where suitable 
sites are near by, preservationist opposition arises, as with 
Storm King Mountain near New York City. Underground installations 
could overcome both the topographical and preservationist obstacles. 
Nuclear plants also present problems for urban or suburban siting, 
in some cases due to unwarranted fear by the public of accidental 
radioactive emissions. Warm water discharges from condensers also 
have led to opposition. Underground placement of nuclear plants 
can give assurances of isolation during accidents and greater pro¬ 
tection against sabotage. Surface reservoirs of a flood control 
and pollution abatement scheme might possibly serve also as cooling 
ponds. 


DESCRIPTION OF POWER INSTALLATIONS 

A simplified section through an underground pumped-storage and 
nuclear power project is shown on Figure 1. The principal elements 
are: 

1. An upper reservoir, lake or ocean. 

2. An upper intake and discharge structure, and access 
building. 


8l 


3. Vertical shafts for pentrocks, for access and cables, 
and for chamber construction and air vent. 

4. Lower level equipment chambers for reversible pump- 
turbines, electrical equipment, and the possible 
nuclear reactors and turbine-generators. 

5. A lower reservoir serving the pumped-storage project 
and the possible nuclear plant condensers. 

If not part of a flood control scheme, the lower reservoir of such 
a power project needs to be from 2,000 to 3,000 ft. deep to be 
economical. If the excavated reservoir chamber is essential for 
other than power use (e.g. flood control), the pumped-storage 
and nuclear generating plant would be economical at much lesser 
depths. A plan of the lower level chamber for the power develop¬ 
ment alone is shown on Figure 2. This arrangement provides for 
cooling water flow into the condensers and pumping of heated water 
to the surface reservoir. 

Both in section and in plan, the power development can be adapted 
to a multi-purpose flood control and pollution abatement scheme. 

The large pumping capacity of the reversible pump-turbines would 
permit rapid evacuation of the lower reservoir after a flood. In 
a single-purpose flood control scheme, equivalent large pumps would 
be very expensive for their very infrequent use. 


FUNCTION OF PUMPED-STORAGE 

The uses of pumped-storage projects are so generally well known 
that only brief mention is needed here. The major functions are: 

1. Load center reserve. 

2. Short-term peaking. 

3. Load regulation. 

4. Energy economy. 

As reserves, such plants can be a source of start-up power for 
thermal plants, as was needed in the 1965 Northeast blackout. 

For short term peaking and load regulation, pumped-storage plants 
offer a faster response to load changes and greater efficiency under 
variable loads. An example of this type of operation is shown on 
Figure 3. 

As more and larger fossil and nuclear fueled plants are installed, 
advantages arise in the use of pumped-storage to conserve low-cost, 
off-peak energy for on-peak use, with a resulting energy econony. 

An example of this type of operation is shown on Figure 4. 


82 


NUCLEAR POWERPLANT COMBINATION 

The use of an underground reservoir for condenser water at a nuclear 
plant creates complications in the configuration of the lower chamber 
and in pumped-storage operation. On the other hand, the access 
sharts and other power plant facilities of a pumped-storage project 
could serve an economical dual function for the nuclear plant. Greater 
public acceptance and the economic advantages of urban siting would 
be the principal determining factors for inclusion of nuclear plants 
in the multi-purpose scheme. 


FLOOD CONTROL AND POWER OPERATIONS 

In any multi-purpose reservoir one function takes priority, or a 
compromise in functional uses is established. In the case of Lake 
Mead behind Hoover Dam, compromises are made in operation, but 
generally irrigation and municipal water supply have priority over 
power generation. There have been years when so-called "prime 
energy" from the Hoover powerplant has been only 60% of the contract 
amounts. 

All generating plants, whether hydroelectric or thermal-electric 
do not offer 100% reliability. For the former, forced outages of 
equipment are rare, but extreme low-water conditions can curtail 
output. Fossil-fuel plants have more frequent equipment outages 
and occasional fuel shortages. Nuclear plants have experienced the 
greatest equipment failures, but no lack of fuel. 

Multiple use of underground reservoirs for flood control and pumped- 
storage would create some conflict in uses, and cause partial or 
total reduction in generation. However, the infrequent use of the 
full volume for floods would cause much less outage of generation 
than is normal for other types of plants. In a study made for the 
Chicago Area, reductions in generation over a 96-year historic 
period would have occurred less than 0.1% of the operating time. 

One example of the combined use of lower and upper reservoirs 
for flood control and power generation during a storm is shown on 
Figure 5. There is indicated for this rather severe storm some 
curtailment in generation and a small amount of overflow of un¬ 
treated sewage to the waterway. Neither the curtailment nor the 
overflow are significant. 


COSTS 

Any flood control and pollution abatement scheme must be accepted 
by the community on the basis of its costs versus the economic and 


83 


intangible benefits. The addition of pumped-storage generation 
can contribute a commercial revenue to the multi-purpose scheme 
that exceeds the incremental cost of the power features. 

Single purpose pumped-storage projects in the U. S. now have a 
construction cost of $100 to $150/kilowatt. The incremental 
constructions cost of the pump-turbine installation in a flood 
control scheme is about $75/ki1owatt. In the case of the Chicago 
Regional Plan, about 20% of the cost of the single-purpose, flood 
control works could be carried by the hydroelectric generating 
pi ant. 

No estimate has been made of the costs or benefits from under¬ 
ground nuclear installation in this type of multi-purpose 
development. 


INSTITUTIONAL PROBLEMS 

It is relatively easy to determine the technical feasibility and 
economic value of the addition of generating facilities in a flood 
control and pollution abatement scheme. The institutional and 
legal aspects create substantial obstacles. 

Agencies in charge of flood control and/or sewage treatment do not 
usually have the capability nor the legal powers to enter into the 
electric power business. On the other hand, the utility companies 
have an obligation to meet the growing power demands of their 
service area, and cannot rely on the uncertain actions of other 
agencies. 

Because of costs, it is not feasible for a utility company to 
construct an underground pumped-storage project that could serve 
for flood control. Agencies empowered to construct underground 
flood control reservoirs are dependent upon federal, state and 
local legislatures for the funding and timing of their projects. 
This makes it most difficult for a utility company to guarantee, 
on an equity or purchase basis, that the supplemental pumped- 
storage power can be absorbed by the urban electrical system at 
a fixed price. 

Despite these problems, there are precedents in the U. S. for 
mixed public and private cooperation in multi-purpose development. 
The successful examples have had the benefit of properly written 
legal charters and strong political support. 


84 


CONCLUSION 


In today's complex society, the many needs of our urban communities 
and the possible beneficial developments must be considered from 
a multi-functional viewpoint. The theme of this seminar is the 
use of our underground urban potential for combined sewer overflow 
and flooding problems. Both hydroelectric and nuclear power plants 
can be valuable complementary functions. 


QUESTION: 

Did you make any estimate of the amount of heat that could 
be dissipated through this underground system? 

SORENSON: 

There would be no heat dissipated as far as the underground 
installation itself is concerned. The only way it could be 
dissipated is on the surface through such things as cooling 
ponds. 

QUESTION: 

Is pumped storage an essential part of the Deep Tunnel Plan 
from an economic standpoint? 

SORENSON: 

It is not essential, but it contributes through commercial 
revenue and through the large capacity pumps which could 
not be considered in a single purpose reservoir. 

QUESTION: 

What is the overall electrical and mechanical efficiency 
of the system? 

SORENSON: 

The hydroelectric equipment is very efficient. Turbines 
are generally around 90% and generators around 97%. The 
use of energy, taking off-peak energy and converting to 
on-peak energy, requires an input of about 1.4 kw-hrs for 
every 1.0 kw-hr received. The relationship is the same 
for both the hill top and underground storage. 

QUESTION: 

How much could the required nuclear power capacity be re¬ 
duced if this were adopted? 

SORENSON 

They do not replace nuclear plants. The two are comple¬ 
mentary. There is more total energy required in a com¬ 
bination pumped storage with nuclear or fossil fuel plants. 

QUESTION: 

If pumped storage replaced older less efficient steam 
plants, would the overall heat loss still be the same? 

SORENSON: 

There would be an offsetting effect. 

QUESTION: 

Are there any problems involved with using sewage in the 
generators? 

SORENSON: 

No, we do not anticipate problems. 


85 



UNDERGROUND PUMPED-STORAGE 

SECTION 

( FIGURE I ) 


86 




















































87 


PUMPED STORAGE-NUCLEAR PLANTS 
LOWER LEVEL PLAN 














































Doily Power Demand - megawatts 


12000 


11000 


10000 


9000 — 


8000 


7000 — 


6000 


DAILY LOAD CURVE 
August 1974 




Pumping 


Pumped - Storage 
P c king 



- 1 - 1 - i - l .i- 1 -1 - I -■ i - i - 1 . 1 -1--1 -4 


8 


16 


Time - hours 


24 


FIGURE 3 


88 





























Daily Power Demand - megawatts 


12000 


11000 


10000 - 


9000 


8000 - 


7000 4 - 


6000 


DAILY LOAD CURVE 
August 1974 



Pumping 


Pumped* Storage 
Energy Economy 


7777 ) 



Mil 1 - i- Li i 1 I - 1 —1 1 1 |6 I 1- : 1-4—l 


8 


24 


Time - hours 


FIGURE 4 


89 

































90 
















































































Session 3 


EXPERIENCES WITH HARD ROCK TUNNELING AND MECHANICAL, MOLES 


Moderator - W. T. Painter 


91 












Section 6 

EUROPEAN DEVELOPMENT AND EXPERIENCE WITH MECHANICAL 
MOLES IN HARD ROCK TUNNELING 

by 

Pieter Barendsen 

Chief Engineer, Product Development 
Atlas Copco MCT AB 
Stockholm, Sweden 


93 









INTRODUCTION 


The subject we are dealing with during the first part of this morning's 
session - i.e., "European Development etc." - might be construed to 
indicate the existence of a certain rivalry in the development of full 
face boring equipment between Europe and the US. 

A historical review too may contribute towards such an impression. On 
24th March, 1853 A. F. Edwards, the man who had planned and estimated 
the cost of the Hoosac Railway Tunnel to the last dollar - $1,948,557 
no more and no less - reported: "The first model of Wilson's patented 
stone-cutting machine for tunnel excavation in rock is now at the 
Hoosac Mountain. The result of its working in the natural rock has 
been from 14 to 24 in./hr., on a full circle of 24 ft. diameter." 

From this he proceeded to line up a detailed working schedule, sub¬ 
stantiated by calculations showing that with two machines one at each 
end, the entire excavation would take exactly 1,005 days. 

The Wilson machine seems to have driven a total distance of 10 ft. 
before being consigned to the scrap-heap, a fate shared by two further 
machines, attempting to cut diameters of 17 and 8 ft. respectively, in 
the same tunnel. Subsequent events showed that Edwards had gravely 
underestimated the technical difficulties in general of this tunnelling 
project: Hoosac, with a total length of 24,416 ft., took just under 
20 years to complete and the costs totalled some $10 million. And, 
while there exists no doubt that out of the Hoosac mess ascended the 
American compressed-air industry which took world - leadership in 
developing and providing the mining and construction industry with the 
early machines and tools for the mechanization of underground rock 
excavation work, it is equally clear that technological developments 
at that time just had not advanced far enough to create workable full 
face boring machinery. 

Knowing what we do today about the problems of tunnelling by mole, the 
results reached as early as 1884 with Col. Beaumont's 7 ft. diameter 
machines - the first to go on record as being successful in hard rock - 
are really quite impressive: one of these drove about 115 ft./week in 
sandstone in the first Mersey tunnel in England, while the other bored 
a total distance of 8,400 ft. in chalk in a pilot tunnel under the 
Channel, maintaining an average speed of 50 ft./day for not less than 
53 working days at a stretch. The machines worked with kerfing tools 
on a rotating head and were powered by compressed air. (Fig. 1) 

In the years between 1884 and 1953 a dozen machines were designed and 
tested, most of them in Europe, but none of them really progressed 
beyond the prototype stage. 

All of the manufacturers presently engaged in the full face boring 
business - my own firm being one of them - will readily admit that 
the US firm of James S. Robbins and Associates did most of the 


95 


pioneering work on the present generation of moles. Development work 
began in 1953 and a first machine, still partly equipped with kerfing 
tools, was put to work in 1954, reaching an advance of some 10 ft./hr. 
in interbedded sandstone, limestone and shale with compressive 
strengths of up to 27,000 psi. 

Today still, the majority of moles in use are of US design, even if 
some of them have been built under license outside this country. 


ROCK HARDNESS 

Before we investigate in which way modern full face boring develop¬ 
ment in Europe deviates from US praxis, I would like to pause for a 
moment and look at the meaning of the term "Hard Rock" which occurs 
in the titles of quite a few of the presentations made during these 
two days. 

According to international contracting practice, all material 
occurring within the earth's crust is regarded as rock, if it is so 
hard that drilling and blasting or some similar, high-energy process 
must be used to break it up. 

It has, unfortunately, become customary to relate the rock's hard¬ 
ness - i.e., its resistance to boring - to its compressive strength, 
expressed in psi, while a suitable expression for the cohesive 
strength of the rock is what is really relevant. 

When we consider the values of compressive strength quoted in 
literature for some of the more common types of rock (Fig. 2), it 
is evident that different rocks vary considerably in hardness and 
that considerable spread exists for rocks of the same type. 

This not only depends on the fact that there is a large variation 
for rock types with the same petrographical designation in different 
parts of the world, but also on the actual testing procedure used. 

In publications dealing with full face boring we often find one 
single maximum value quoted for the compressive strength of the rock, 
while nothing is said about how this value was obtained or what 
proportion of the total volume of rock is represented by the sample 
quoted. This is very unsatisfactory. To compare the "borability" 
of different types of rock in a meaningful way the following factors 
should be taken into consideration: 

1. The compressive and the shear strengths of samples of fresh, 
homogeneous and non-fissured rock. The shape and size of the 
sample and, in the case of bedded rock, its orientation as well 
as the testing procedure, method of preparation, moisture 
content, loading rate and number of measurements, should be 

regulated internationally or at least be specified for each 
individual test. 


96 


2. The Mohs' hardness or some other comparative hardness value for the 
minerals in the sample, together with the grain size and the 
distribution of mineral constituents. 

3. Fissures, cleavage planes and other discontinuities in the ranges 
of 0.4 to 2.0 in. and 2 to 20 in. 

4. The abrasiveness of the rock, expressed by the volumetric 
percentage of quartz and felspars, or by a standardized abrasion 
test. 

5. The porosity of the rock as well as the matrix material between 
individual crystals or mineral grains. 

In the case of a tunnel driven at great depth, rock pressure should 
also be taken into account, as this may be a factor which could make 
the rock easier or harder to bore. 

In spite of the imperfections of the compressive strength as the sole 
yardstick for measuring the borability of a rock, it is widely used, 
mainly because it is a value which can be established rapidly from 
small samples such as diamond-drilled cores. It would seem to be of 
the greatest importance that the authorities responsible for the 
design and construction of tunnels and other underground openings 
should improve substantially the quantity and the quality of the 
information made available at an early stage to those who will have to 
carry out the actual excavation. The argument that such pre-tendering 
investigations would raise the cost of the completed tunnel is not 
valid. On the contrary, the increase in cost would be more than 
offset because the contractors would not feel obliged to load their 
bids so as to safeguard themselves against the financial consequences 
of unknown and unfavourable rock conditions. 

For the purpose of further discussion I think that, no matter what 
each of us sees as the most important factor to describe "the hard¬ 
ness of the rock," we can agree upon such a definition of "hard rock 
tunnelling" that it automatically excludes the use of shields for 
the support of unstable or running ground. 


DIAMETER RANGES FOR HARD ROCK TUNNELLING MACHINES 

As moles usually are designed for specific tunnel diameters, we might 
review what range one is nowadays attempting to cover. 

As we know, tunnels are driven for many different purposes and with 
widely varying cross-sectional areas. (Fig. 3) 

Some of them have such small diameters that they should rather be 
considered as underground conduits and these are usually constructed 
in soil or very soft rock formations by means of augering or tubepressing. 


97 


A diameter of 6 ft. must be considered as the lower limit for excavation 
by explosives or by means of a full face boring machine operating in¬ 
side the tunnel and most civil engineering experts tend to regard 20 ft. 
as the approximate upper limit for economical boring operations under 
normal conditions today. Special circumstances, such as the presence 
of easily bored, weak rock which would need elaborate support if 
blasted or when tunnelling is done close to existing buildings or under 
water, have sometimes established their own scale of economic value and 
led to the use of machines of some 30 ft. in diameter. 

Examples of such very large machines are the Robbins mole used at the 
Mangla Dam, later rebuilt and now in use at the second roadway tunnel 
underneath the Mersey; the Robbins machine used on the Paris subway and, 
more recently, the Robbins mole for the Heitersberg Railway tunnel in 
Switzerland and the Wirth two-stage machine (25 and 35 ft. diameter) 
for a roadway tunnel near Lucerne in that same country, reaming from a 
12 ft. diameter pilot bore. 

Generally speaking, one may conclude that within the field from 6 ft. 
to 20 ft. diameter the choice of excavation method applied is dependent 
on the quality of the rock and economic conditions rather than on the 
diameter. 


VARIOUS TYPES OF EUROPEAN MOLES 

The rock boring machines available for tunnelling in Europe today, 
may be divided into two groups, according to the method of operation: 
Machines that work the full face of the tunnel at any moment, while 

being advanced continuously along the tunnel axis. 

This is the type of machine which, in this country, is usually 
described by the term "mole". Presently, three manufacturers in 
Europe offer this type of equipment: Wirth and Demag in Germany and 
Atlas Copco of Sweden through their subsidiary in Switzerland. (Fig. 4) 

All of these machines bore tunnels with a circular cross section, 
because the cutter-or boring-head is rotated around an axis that 
coincides with that of the tunnel itself. Diameters for which 
standard machine designs are available more or less "off the shelf," 
range from just under 9 ft. to just over 14 ft. In this respect Europe 
seems to follow normal US trends. 

Machines with one or more cutter heads of dimensions substantially 

smaller than the tunnel cross section which work the face by a 

combined rotating and sweeping movement and are advanced stepwise in 

the longitudinal direction of the tunnel. (Fig. 5) 

Such machines can, because of their design, cut a tunnel of non¬ 
circular cross-section and are, therefore, of special interest in 
mining operations where a flat footwall is required for haulage pur¬ 
poses. The majority of these machines are equipped with "pick- 


98 








type" tools and have not been designed to work rock any harder than 
the relatively soft formations encou tered in coal mining. Well 
known manufacturers in the field are: Mayor & Coulson, Greenside- 
McAlpine, Bretby and Dosco in England, Eickhoff and Demag in Germany 
and Alpine in Austria. A number of machines for use in soft materials 
like coal, gypsum and salt have also been developed in the USSR, from 
where they have spread to other countries behind the Iron Curtain. 

Recently Atlas Copco have entered this field with designs suitable 
for work in hard rock. These machines use the same type of cutters and 
cutter heads as are used on the standard machines for circular cross 
sections produced by this firm, but in different configurations and 
with a different pattern of movement in space. 


CUTTING TOOLS 

One of the main problems in tunnelling without the use of explosives 
lies in the development of tools which, at an economically acceptable 
level, are capable of continuous breakage of the rock, resulting in a 
fragmentation suitable for a smooth, uninterrupted transportation of 
the muck away from the tunnel face. 

Tools employed on tunnelling machines have, so far, always been of the 
mechanical kind which break up the rock by a crushing and shearing 
action. Other methods of rock breaking are possible but, even if some 
of them have reached the laboratory testing stage, nearly all of them 
are still too "exotic" to be of any practical use in the immediate 
future. 

One must admit, however, that some highly interesting results are 
beginning to be reported from this country on the use of high pressure 
water jets for the destruction of rock by erosion, a field pioneered in 
Europe (USSR and Great Britain). 

Mechanical breakage of rock is effected by inducing stresses exceeding 
its compressive/shear strength by loading it with a wedge or cone- 
shaped tool until cracks are formed and chips are loosened. In order 
to allow the tools to act upon the rock face continuously, they are 
commonly shaped as rotating bodies, "roller bits" or "disc cutters," 
spinning freely and mounted on a revolving boring head of tunnel 
diameter. (Fig. 6a, b). The thrust of the tools against the face is 
generally exerted in a direction which is parallel to the tunnel axis. 

The roller bit, which was inherited from the oil industry, is the older 
of the two and has so far predominated for work in hard rock. The disc 
cutter, because of its generally somewhat lower cost per foot of 
tunnel and smaller production of fines, is fast making inroads, even 
for work in hard rock like granite and gneiss. 


99 


The rock may also be worked by fixed cutters such as "picks" or 
"tips" which are moved alonga linear or curved path to cut a groove in 
the tunnel face. (Fig. 6c) These tools are usually arranged so that 
the main cutting forces occur in a plane at right angles to the tunnel 
axis. An important consequence of this arrangement is that machines in 
which such tools are employed do not require such high thrusts against 
the face as do tunnelling machines in which rotary cutters are used. 

Possibly influenced by early experience with cutting or "ripping" tools 
in coal mining, many have considered them less suitable than roller 
cutters for work in harder rock. During recent years this opinion has 
been proved wrong. (Fig. 7) 

At the 1968 Tunnelling and Shaft Sinking Conference held in Minneapolis 
by the University of Minnesota, Dr. Nevil Cook of South Africa indicated 
what requirements of cutting geometry have to be met for the cutting of 
hard rock. The fact that these are not purely theoretical observations 
has been proved by recent Rock Cutter field tests carried out by the 
Chamber of Mines of South Africa in order to arrive at a non-blasting 
stopping method for the deep lying gold mines in that country. 

Figures are available from Switzerland too which show that this kind of 
tool is suitable for the cutting of hard and abrasive rock - a 
quartzitic sandstone with a compressive strength varying from 25,500 to 
34,000 psi and with a quartz content of not less than 60 per cent - 
while the total tool costs for the tunnelling machine in question, 
including the cost for renovation of the tool holders, were slightly 
below the costs for drill steel, explosives and blasting caps in that 
part of the same tunnel which was driven by the conventional method. 
(Julia hydro electric power station, 1967/68) 

While on the subject of cutting tools, it may be of interest to note 
that each of the three European mole manufacturers in the beginning 
selected a different kind of tool. 

Wirth, starting off with tools manufactured under license to the Hughes 
Tool Company, concentrated on roller bits which, for use in harder 
rock, were of the TC button type. Some costly experiences when driving 
a down grade tunnel in granite in the Austrian Alps led them to a 
different design of the cone shape and of the bearing and sealing 
arrangements and they subsequently developed and have now standardized 
on tools of their own design. Some two years ago they began experiment¬ 
ing with TC studded disc cutters which proved to be more economical 
during a 3,500 ft. long raising job at a 60% incline for pen stock 
excavation in some hard Swiss granite and gneiss formations last year. 
Today they offer both roller bits and disc cutters as standard tools 
with interchangeable bearing and saddle arrangements, so that the most 
suitable tool may quickly be installed with changing ground conditions. 


TOO 


Demag have always used disc cutters, usually with two or three discs 
combined in one bit body. No doubt, our next speaker will go deeper 
into this. 

The machines now marketed by Atlas Copco, have always used TC tips. 

As they, through their cutting geometry, differ substantially from 
all other types of tunnelling machines, I will now highlight some of 
their features. 

SPECIAL FEATURES OF TUNNELLING MACHINES WORKING ON THE UNDERCUTTING 
PRINCIPLE 

The inventor of the system for cutting rock in a radial direction by 
means of a number of separately driven cutter heads equipped with TC 
tipped tools, mounted on a slowly revolving boring head of tunnel 
diameter, was the late Joseph Wholmeyer, an Austrian engineer, who 
took out the first patent as early as 1951, two years, incidentally, 
before Robbins started in the tunnelling machine business. The system 
was, at one stage, applied by the German firm of Krupp on an experimen¬ 
tal machine for rather soft rock formations - mudstones of approximate¬ 
ly 3,000 psi compressive strength - and was in accordance with the 
original intentions of the inventor, but after his death in 1964, 
developed further to make it suitable for the cutting of hard rock, 
first by the Swiss firm of Habegger and, since the close of 1968, by 
Atlas Copco which firm now owns all the patent, manufacturing and sell¬ 
ing rights. 

The reason why it took some 15 years to reach the stage where efficient 
and reliable machines could be built according to this principle, is 
that it took a long time before the secret was found of how to achieve 
acceptable tool economy - namely, that cutting had to be carried out 
at low speeds (20 - 50 ft./min.), with considerable cutting depth 
(3/8 in. to 3/4 in./tip) and without tool - chatter, thus requiring a 
very rigid machine design - and that it took years of research and 
testing to develop tough and yet wear resistant grades of tungsten- 
carbide. 

By inclining the cutter heads to the machine axis and by advancing the 
boring head which carries the cutter heads with a speed related exactly 
to its rotation, the cutters are caused to penetrate the rock in 
concentric, helical paths, cutting the walls of the tunnel like a 
multiple-start internal thread. (Fig. 8) 

This layout makes it possible to "undercut" the rock so that only 
about one-third of the total volume is worked by the cutter tips, while 
the remaining two thirds, in the form of an uncut ridge immediately 
behind the cut, is broken away by a slight rearward pressure exerted 
by a wedge-shaped protrusion behind each cutter tip and rotating with 
it. (Fig. 9) Along the tunnel walls the rough surface, produced when 
the ridge is broken off, is trimmed by finishing cutters to protrude 
not more than 1/8 in. to 1/4 in. above the bottom of the groove cut by 
the main tools. 


101 


The radial cutting action requires little thrust against the face and 
the forward reaction on the tools when they undercut the rock reduces 
it still more. It has been found that undercutting machines need no 
more than about 10 to 30 per cent of the thrust required by machines 
working the rock with rotary tools. This is a great advantage not 
only because it reduces the load on the main bearing, but also because 
it decreases the problem of finding sufficient anchorage for the 
propulsion unit in soft or broken ground. In addition it simplifies 
maintaining alignment of the machine in rock of varying hardness. 

The higher the thrust, the greater is the tendency for a boring 
machine to veer towards the softer zones. This throws excessively 
high side loads on the main bearing and explains why an American-made 
tunnelling machine had to be withdrawn with a collapsed main bearing 
after boring somewhat less than 600 ft., while an undercutting machine 
drove a further 2,900 ft. in the same tunnel and in the same ground 
without any such difficulty and without ever being more than 1 1/2 in. 
off line. (Julia hydro electric power station, 1967/68) 

It must be self-evident that far better tool economy is obtained if 
only a third of the total rock volume is cut than when the entire 
rock mass excavated from the tunnel is worked by the cutting tools. 

The undercutting principle also reduces the production of fines which, 
especially in wet tunnels, lead to considerable wear on the muck 
removal system through the formation of, often highly abrasive 
slurries. Screen-analyses of the muck produced by undercutting 
machines in various types of rock show that the fraction below 3/8 in. 
constitutes less than 10 per cent of the total volume. 

Tunnelling machines in which rotary cutters are employed work the 
rock face frontally so that the tools cannot penetrate sideways. 
Steering can, therefore, be carried out only by swinging the rear of 
the machine around a point close to the tunnel face. Due to the over¬ 
all length of the machine, the minimum curve-radius is usually not 
less than 300 to 400 ft. 

Undercutting machines work the rock in a radial direction their tools 
can penetrate the tunnel walls and steering may, therefore be executed 
around a point at an appreciable distance behind the face, leading to 
a shorter curve-radius, especially when the machines are built in 
articulated sections. 

An interesting example in this respect is the machine which Atlas 
Copco started up recently at the White Pine Copper mine in Michigan 
(Fig. 10). 

It can negotiate curves with a radius of no more than 40 ft. to the 
centre line and slopes of 20% up or down. The four rotating cutter- 
heads of 4 ft. diameter are mounted in groups of two, undercutting 
the rock in a sweeping motion, (Fig. 11) like windscreen wipers and, 
like them, overlapping in the centre to produce a mainly rectangular 


102 


opening, with an absolutely flat footwall and back and slightly 
curved sides, of 16 ft. width and 8 1/2 ft. height. These features 
make the machine extremely suitable for mining purposes. (Fig. 12) 

The machine has been laid out to bore 1,000 ft./month, double 
shifting, in the slightly metamorphic, bedded White Pine ore formations 
of shales and interbedded sandstones with a compressive strength 
between 18,000 and 28,000 psi. Though it is obviously too early to 
say, preliminary reports indicate that this target is likely to be 
reached from a cutting performance point of view. Due to a series of 
up-throw faults, the machine operated with the two lower cutter heads 
working in very much harder than normal sandstone underlying the ore 
formations when emerging from the erection chamber. Though this 
sandstone obviously caused increased tool wear, the cutting speed did 
not suffer appreciably. 

Another machine for non-circular openings now being built by Atlas 
Copco should be of interest to the construction industry for the 
excavation of the outer-most branches of sewage and water reticulation 
systems, cable ducts etc. under densely populated areas. Weighing no 
more than a total of 25 tons and consisting of two main parts of 18 
and 15 ft. length respectively which can easily be lowered to tunnel 
level through a shaft from street level, the machine will cut open¬ 
ings of 4'3" width and 7'0" height in the centre, with straight, 
vertical sides, a slightly dished invert and a semi-circular roof line. 


EXPERIENCE OF UNDERCUTTING MACHINES 

So far, a total of four machines for circular openings working on the 
undercutting principle have been produced and put to work, apart from 
the original Wohlmeyer prototype. 

Three of the machines, ranging from 12'0 11 to 13'3" in diameter and 
partly manufactured under license in Japan, were used for exploratory 
work - pilot tunnels - for the Seikan project in that country, where 
a railway tunnel is to be driven to link the main islands of Honshu 
and Hokaido. Two of these are at the moment in service and have 
driven some 5,000 and 2,000 ft. respectively. 

These figures may not seem impressive, but they have been reached 
under partly very severe, adverse conditions. Large inflows of water 
and extremely bad ground conditions have, for months at a time, 
limited advance to not more than 50 ft./month. I think you will agree 
that it would be rather pointless to quote any figures from such a 
non-representative job. Let is suffice to say that excavation by 
conventional methods would have been completely out of the question 
under such conditions. 


103 


The fourth machine has been in service in Switzerland since 1967 and 
is now on its second job, excavating an 11'3" diameter sewage tunnel 
with a total length of 3 miles near the town of Rorschach. 

The rock there consists mainly of a rather tough sandstone, with 
compressive strengths ranging from approximately 12,000 to just over 
28,000 psi and containing some 60% of free quartz with a calcitic 
binder. For the 9,000 ft. excavated to date the contractor estimated 
that the average compressive strength has been in the vicinity of 
22,000 psi. During this period the average advance has been 40 ft./ 
day of 20 working hours. The best day gave 73 ft., the best 5-day 
week 250 ft. and the best month 1,050 ft. so far. 

Average boring time of the total available working time has been 
just over 60% - with some weeks running as high as 75 to 80% - while 
tool changes and machine maintenance each accounted for 10% of the 
working time. The remaining 20% was lost due to delays behind the 
machine. I think these figures tie in pretty well with the average 
US results reached on a wel1-organized construction job. 

Tool costs, including costs for renovation and depreciation of the 
tool holders and for labour during tool changes, have so far averaged 
$10.50 per running foot of tunnel. This amounts to $2.65/cu. yard 
excavated. For this kind of rock this must be considered as a very 
low figure and is, of course, due to the fact that the tools are under¬ 
cutting and only work 1/3 of the total rock volume excavated. 

From the engineer who runs the job down to the old man who sweeps the 
floors and makes the coffee, the total crew on site exists of 16 men, 

10 on day shift and 6 on night shift. Total cost of the operation, 
including transport of the rock out to the tip and with machine depre¬ 
ciation calculated over a total distance of 4 miles, amount to 
$57/1 inear foot, though you will find it hard to get the contractor to 
admit this. 


CONCLUSION 

Judging from the fact that tunnelling machines working on the under¬ 
cutting principle 

-offer a free choice of the shape of the opening produced, 

-can negotiate tight curves, 

-operate at low thrust and anchoring forces, 

-use one type of tool, independent of rock hardness, 

-cut the rock with suitable fragmentation at moderate tool costs, 

one is inclined to conclude that the undercutting principle enables 
us to design very flexible and economical to operate tunnelling 
machines. 


io4 


Continuous research to improve tool life in really hard rocks, 
carried out in close cooperation with tungsten-carbide experts and 
other metallurgists, contributes towards making these machines 
capable of meeting the widely varying tunnelling requirements of the 
mining as well as of the construction industry. 




i 


105 



Fig.l 


106 








Sandstone 
Shale 
Granite 
Limestone 
Dolomite 
Taconite 
Quartzite 

Compressive strength 1000 2000 3000 4000 5000 6000 k p/cm 2 

14,200 28,400 42,700 56,900 71,100 83,300 psi(approx.) 

Variations in compressive strength of some rocks 



Fig. 2 


Diameter m 

1 2 34 5 6 78 9 10 11 

Hydro-electric tunnels 

Cooling water tunnels 

Cable tunnels 

Road tunnels 

Railway tunnels 

Subways 

Irrigation tunnels 

Sewerage tunnels 

Drainage tunnels 

Water tunnels 

Mines (equivalent dia.) 

Storage tunnels 


1 l 1 1 

l 1 l l I 

^ 


a a s 

ill 

i ■ i 


i l I i i 

Lower limit for conventional methods and 

full-face boring -- 


Present limit for economical full-face 

boring? 


Tunnel diameters and purposes 


Fig. 3 


107 





























































Fig. 5 



108 



























Fig. 6abc 



Fig, 7 


109 










Fig. 8 

b = cutting width 



110 


Undercutting towards a free surface 

Fig. 9 








Fig. 10 



Fig. 11 


ill 


















112 









Section 7 

EUROPEAN DEVELOPMENT AND EXPERIENCE WITH MECHANICAL 
MOLES IN HARD ROCK TUNNELING 

by 

Ernst Weber 

Managing Director, Mining Machinery Department 
Demag Heavy Machinery Equipment 
Wolfgang-Reuter-Platz 
41, Duisburg, West Germany 


113 


PRACTICAL EXPERIENCE IN THE FULLY-MECHANIZED 
DRIVING OF GATES, DRIFTS, ROADS AND TUNNELS 


GENERAL 

At the beginning of my paper I should like to illustrate the extent of 
the distances that have to be driven through rock throughout the world. 
On the basis of this data one can recognize the importance of fully- 
mechanizing the driving of gates, drifts, roads and tunnels. 

At the present time the following distances are driven by the West 
German hard coal mining industry for an output of some 100 million 
tons per year: Approximately 76 mi. of stone drifts and cross cuts 
per year, approximately 340 mi. of gates, drifts and roads per year. 

This corresponds to a specific driven length of about 4 mi. per million 
tons per year. 

An estimate of underground mining of all minerals throughout the world 
puts the output at not less than 1.9 thousand million tons per year. 

The total length of the distances to be driven throughout the world 
underground would hence be approximately 1900 x 4.0 mi. = 7,600 mi. per 
annum. The civil engineering industry (canalisation, water tunnels and 
similar projects) would increase this by about 5%. 

It is interesting to compare these figures with statistics obtained 
from the South African Mining Industry. During the last 10 years in 
that country alone, an average of 630 mi. per year were driven under¬ 
ground. It is safe to assume that the remainder of the world's under¬ 
ground mining industry needs to drive more than 12 times the distance 
required by the South African Mining Industry. 

The approximate 7,600 mi. per year are driven at a cost of 500 German 
Marks for every 3 ft. 3 in. driven ($44/ft.), equivalent to a total 
expenditure of at least 6 thousand million German Marks per annum 
($1.7 billion/yr). With an average figure of 1 ft. per man and shift, 
probably more than 250,000 men are employed all over the world on 
underground driving operations (this takes into consideration absen¬ 
teeism, etc.). 

It is obvious that these figures illustrating the development of under¬ 
ground tunneling and mining have repeatedly encouraged the investigation 
of the possibility of mechanizing tunneling and drifting. A consider¬ 
ation of social aspects is also important. The number of accidents 
occurring during conventional tunneling and drifting is radically re¬ 
duced by the employment of fully-mechanized tunneling equipment. Main¬ 
tenance of the health and the ability to work of several thousand 
skilled workers underground is to be welcomed from all points of view. 

If it is borne in mind that underground mining is taking place at great¬ 
er and greater depths and higher rock formation temperatures are hence 


encountered, it may be seen that mechanization also makes the miner's 
work easier. 


DEVELOPMENT 

As early as 1856 a tunneling machine was used for the first time for a 
preliminary investigation of the Channel Tunnel Project. Today, after 
more than 100 years of development works, tunneling machines employ 
almost the same principle. 

During the last 10 years, mechanical tunneling techniques have become 
so sophisticated and improved that the economical employment of modern 
machinery is beginning to gain ground as compared with conventional 
methods. Drifts and tunnels, many miles long, have already been 
mechanically driven today, and for most projects, in addition to con¬ 
ventional driving, tenders are also invited for fully-mechanized driving. 
It is to be anticipated, that in the near future, developments will 
further shift the economic aspects still more in favor of fully-mechan¬ 
ized driving. This trend may be illustrated by a few examples: 

The tunnel in the Swabian Jura in South Germany for supplying 
water to the Stuttgart area from Lake Constance had a length 
of more than 11.6 mi., diameters of 8 ft. 2 in. and 9 ft. 2 in. 
and was completely driven in barely three years. Several tun¬ 
neling machines were employed simultaneously at different 
points. 

Machines with very large diameters have been employed in the 
construction of underground railways in large cities through¬ 
out the world such as New York, Budapest, Vienna, Paris, 

Munich, Hamburg, Moscow and Leningrad. Partial mechanization 
in the construction of the underground railway in Prague, 
Czechoslovakia, has already been employed and is being extended. 

In the Harz Mountains in the Federal Republic of Germany a 
water tunnel about 5 mi. long is presently being driven and 
will be completed shortly. Very difficult conditions, such as 
hard rock with faults and very high rates of intrusion of water, 
were coped with here. 

Inclined shafts for power stations were drilled in granite in 
the Swiss Alps. 

In Japan it is planned to drive hundreds of kilometers of ex¬ 
press tramway tunnels of very large diameter for linking one 
island to another. 

Beneath various large German towns, sewage tunnels are reg¬ 
ularly driven by tunneling machines. Examples are in Dortmund 


115 


and Wuppertal. 

In Liverpool a large road tunnel with a diameter of more 
than 10 meters (32 1/2 ft.) was built in the dock area 
by a tunneling machine. 

Underground caverns are made by full face headers on face 
heading machines in hard and soft rock formations. 

There is a very wide range of applications in the hard coal 
mining industry in Germany. Large tunneling machines are 
ready to start work at very great depths in difficult ven¬ 
tilation conditions with emission of methane. 


PRACTICAL EXPERIENCE 


Past Performances 

Figure 1 illustrates some of the performances that have been attained 
to date. We have heard of conventional operation in stone drifts and 
cross cuts in Czechoslovakia with world record driving rates of 3170 
ft./month without linings and supports. Indeed, for a period of 6 
months an average of 1846 ft./month were driven. 

With a full face header, more than 6160 ft./month have been attained 
in the USA in medium-hard rock under favorable geological conditions. 

In the Harz Mountains in the so-called Kahleberg sandstone alone with 
a compressive strength of about 33,000 psi and containing about 65% 
abrasive constituents, more than 10,200 ft. has been driven to date. 
Rates of 890 ft./month have been attained. To our knowledge, this is 
the first tunnel in the world which is being driven under such condi¬ 
tions and in such hard rock with a tunneling machine. 

In Stockholm, 394 ft./month have been attained in granite and gniess 
with a compressive strength of about 42,000 psi. This was in almost 
exclusively a single-shift operation. The extremely hard rock encoun¬ 
tered here initiated the development of improved drilling tools. 

Tunneling machines have also been developed for loosening and cutting 
of soft rock. A face heading machine with a soft rock cutting jib, 
which works in a totally-enclosed shield, was developed for driving 
a sewerage tunnel in England with a length of about 5 mi. 

In the inclined shafts in the Swiss Alps, already mentioned, driving 
rates of up to 410 ft./month were attained with angles between 30 and 
40 degrees. The working conditions, which on a conventional basis 
had been difficult, were coped with much more safely by the fully- 


116 


mechanized driving system. 

There is now a large number of manufacturers in the world who have 
devoted themselves to fully-mechanized tunneling and driving techniques. 

I should like to refer to the courage and the development work which 
mechanical engineers, contractors and project engineers have applied to 
problems of fully-mechanizing the tunneling and heading process. To 
our knowledge, in 1969, 25 mi. were already mechanically driven in hard 
rock alone. It is not intended at this juncture to give a detailed list 
and mention the whole range of types of machine. The relevant literature 
and papers in this specialized area have given sufficient information on 
this point. I should merely like to point out that all modern driving 
processes are based on the principle of operation with roller cutters, 
Kerving tools, spirals or cutter bars. 

The drilling process is influenced to a decisive degree by the choice 
of a suitable tool. The best roller cutter tools have been developed 
as a combination of discs of steels highly resistant to wear. Such 
discs are combined with cemented carbide plates. 

The roller-type tools should produce drillings which are as coarse as 
possible and produce optimum advance. However, since the type of rock 
changes frequently in practical operations, a compromise must be aimed 
at in the selection of tools. A special method of arranging the roller 
cutters on the boring head makes it possible to select different dis¬ 
charge widths for the conditions encountered at any time. It is aimed 
at developing tools in which the service lives of the bearings and the 
elements splitting rock are equally long. The idle times necessary for 
exchange are thus substantially reduced. It must be possible to rapidly 
remove the roller cutters towards the front by means of transport equip¬ 
ment. Replacement of a roller cutter proper takes only a few minutes. 

Figure 2 gives a review of the service life of roller cutter tools as 
can be anticipated, to my knowledge, at the present time. 

The rate of advance of a machine equipped with roller cutter tools is 
a function of the contact pressure on a tool or a function of the 
pressure in the hydraulic system. Every type of rock has its own 
characteristic phase. When a minimum contact pressure is exceeded, the 
rate of advance increases much more quickly. In one case we were able 
to establish that between compressive strengths of 36,000 and 42,000 
psi, the rate of advance increased by a marked degree from 1 ft. 9 in. 
to 2 ft. 7 in./hr. when the pressure was increased from 220 to 280 
atmospheres. At this point it is necessary to refer to the wide variety 
of factors which, apart from the compressive strength of the rock, also 
effect the rate of advance. Such factors include the shear strength, 
the degree of intergrowth, the particle size and the proportion of 
abrasive constituents such as quartz, felspar and others. 

At the present time, on the basis of experience gained regarding the 


117 


service life and the cost of tools, we are attempting to render possible 
predictions regarding the costs of future projects. We are aiming at 
being able to make such predictions with the aid of regression analysis 
from rock data corrections by EDP programming. 

A problem particularly affecting the miner is the placing of linings and 
supports at the right time. The circular profile represents the most 
favorable statical form of cross section. In the event of falls or 
formations exerting pressure, it is important to quickly place temporary 
supports in the form of sprayed concrete, rock bolts, steel linings or 
liner plates. 

Figures 3a, 3b and 3c show an example of a modern tunneling machine 
which permits the various types of lining and support to be fitted 
directly behind the cutting head or behind the front clamping unit. 

When a closed ring lining is employed, different types such as bell 
sections, "tub" sections, H-sections, liner plates, steel fabricated 
mats, W. Hernold System plates, etc. may be employed. 

Problems of a special nature arise during driving through zones of 
geological disturbance. When soft or slippery zones occure following 
hard rock zones, this may mean that driving operations have to be stopped 
(when the zones are of some length) because the clamping units do not 
find adequate support. In such circumstances it will be necessary to 
carry out manual driving in front of the boring head. A conveyor ar¬ 
ranged beneath the machine can be drawn through the head for removal 
of the spoil. After linings and supports have been placed the machine 
can then pass through the zone of distrubance under its own power. 

We have already also driven into tectonically disturbed zones in which 
the roof was falling in front of or above the boring head. In this 
case the disturbed zone was filled with a quick-curing concrete in¬ 
jected into the rock (Figure 4). After the concrete had set the machine 
could be driven through these zones. In some instances this procedure 
had to be repeated several times. 

When tunnels and other underground gates are being driven, considerable 
intrustion of water must be expected from the rock. At the moment, on 
a well-known construction site, 38 - 50 USGPM of water are being en¬ 
countered. A large proportion of this occurs in the area of the tun¬ 
neling machine. It has been shown that the mechanical and electrical 
engineering of the machine is so reliable that the purely mechanical 
functions are not impaired. However, this considerable flow of water 
causes a substantial quantity of sludge to be formed. Difficulties 
were encountered in removing this sludge. After intensive investigation, 
this was taken care of by supplementing the conveyor in the lower area 
of the tunneling machine by a special rubber open-top conveyor which 
takes care of transporting the sludge upwards to the level of the trans¬ 
fer point to the mine cars. This enabled the rate of advance under 
these unusually difficult conditions to be doubled. It may be pointed 


118 


out that all other tests with cyclones, sludge filters or pump systems 
were not successful. 


Control of Line and Level and Negotiating of Curves 

Control of line and level of the tunneling machine by means of a guide 
beam generated by a laser has proved entirely successful. It should be 
particularly noted that the laser has to be aligned and monitored with 
extreme accuracy. Deviations from the set line and level are usually 
caused by negligent handling. The authorities responsible for safety 
have recently started publishing comprehensive regulations, and to our 
knowledge an operating license has always been granted. The object is 
to protect the health of men working in the vicinity of the laser. It 
should further be noted that the power (1 mW) of the lasers used today 
in mechanical tunneling practically eliminate any health hazard. Medical 
evidence is available for this. 

Control engineers are at present working on fully-automating the opera¬ 
tion of a tunneling machine. Semi-automatic control has already been 
proven in actual operation. This eliminates operator faults and hence 
prevents consequential damage. In addition, optimum efficiency of the 
tunneling machine is obtained. Though it may appear attractive for the 
technician to build or operate a fully-automated and remotely-control1ed 
tunneling machine, this would be associated with the hazard of excessive 
liability to operating faults caused by the specific mining difficulties 
resulting from high air humidity, poor heat transfer in confined spaces. 
Also accessibility would cause difficulties in monitoring such a control 
system. 

At the present time, when negotiating time, the laser has to be re¬ 
located at short intervals far too frequently. This causes considerable 
loss of working time and hence adversely affects utilization of the 
tunneling machine. A curve control system should, therefore, be develop¬ 
ed which automatically sets the desired curve radius. 

In our experience, negotiation of tight curves is associated with 
correspondingly higher tool costs for the outer diameter cutters. It 
is, therefore, best to plan as large radii as possible when planning a 
route. 


Experienced Gained in Removal of Material 

The method of transporting material inside and behind a tunneling machine 
influences the rate of advance to a decisive extent. On studying the 
cycle of operation, it is found that considerable idle times are caused 
by faults within this transport system. 

Figures 5a, 5b and 5c show in simple form tunneling operations with 


119 


different means of material handling. One essential task of the site 
manager of a mechanized tunneling operation is proper organization. The 
causes of down-times are to be established and rectified at once by means 
of complete and extensive supervision of operation. Down-times during 
operation and sometimes even consequential damage can be prevented by 
exchange of wearing parts during maintenance times. The degree of utili¬ 
zation of the tunneling machine is improved and an optimum rate of advance 
attained. 


Climatic Problems 

As a rule fully-mechanized tunneling is carried out in an area with extra 
ventilation. Design of the ventilation system should be very carefully 
planned. Air requirements depend on the number of men at the face. The 
volume of fresh air supplied should not be less than about 60 cu. ft. 
per man per minute. There should be an additional 90 cu. ft. per minute 
per diesel horsepower. In view of possible gas emissions and in the 
interest of good mixing of the air in the vicinity, the air speed should 
not fall below about 4 in./second. To satisfy these requirements, the 
diameter of the ventilation pipe should be large enough to enable the 
necessary volume of fresh air to be blown towards the front of the tun¬ 
neling machine. Today it is quite possible to effectively operate an 
extra ventilation system even for small diameters over a length of more 
than 3 mi. 

The heat generated by a tunneling machine should also be taken into con¬ 
sideration. An example of this is a 16 ft. tunneling machine which will 
shortly be employed at a depth of about 3100 ft. Cooling equipment with 
a rating of more than 350,000 keals per hour has to be installed. 

Another measure that has to be taken is the provision of a dust shield 
at the front of the machine. By means of water spraying and exhausting 
of the dusty air in conjunction with small cyclones or other wet and dry 
dust precipitators, the dust content in the area where the operating 
personnel are located is reduced to figures which exlude the possibility 
of silicosis and meet the official regulations. In this connection it 
may be mentioned that in many cases where tunnels are being driven it 
was proven unnecessary to have additional dust precipitating equipment 
in an apparatus arranged behind the tunneling machine. 


Design Features of the Tunneling Machine 

One of the duties of the manufacturer of the tunneling machine is to make 
provision for its quick assembly and dismanteling. The very cramped 
space conditions demand optimum design and dimensioning of the individual 
components so that transportation as well as repairs can be carried out 
without extra excavation being necessary in the tunnels and in horizontal 
and vertical bottlenecks. 


120 


When starting to drive tunnels directly from the surface, it has already 
been possible to commission an almost completely assembled machine with¬ 
in one week on a wel1-prepared site. Between 2 and 6 weeks would prob¬ 
ably be needed, depending on the size of the machine, for delivering and 
erecting a machine. Conscientious examination of these transport and 
erection aspects must, therefore, be an essential part of any preliminary 
calculations. 


Tunneling Machines in Soft Rock 

A soft rock can be cut or kerved. The experience we have gained is 
limited to machines which are of the face heading type. In other words, 
one or more jibs fitted with cutter heads carry out selective winning 
at the face. 

The most favorable employment conditions arise when the rock formation 
remains stable until the lining has been placed behind the machine. 

Under such conditions maximum rates of advance can be obtained. This, 
of course, is subject to the availability of a well functioning organ¬ 
ization such as I mentioned earlier in the case of the machine for 
tunneling in hard rock. Face heading machines mounted on crawler tracks 
are employed for such conditions. However, their employment is limited 
by the angle of inclination of a section in the longitudinal or trans¬ 
verse directions. I, therefore, wish to talk about machines which can 
also cope with this difficulty. A technique is employed in which the 
machine is hydraulically clamped all round. With the clamping system 
it is possible to carry out a course correction or to negotiate curves. 

A great deal of experience has been gathered in this area in recent 
times. Course corrections can be carried out by up to 6 degrees in 
single steps. In undulating rock formations in particular, very frequent 
course corrections are necessary, since the seam has to be accurately 
and directly followed. 

A so-called template control system has proven very good for permitting 
a cross section of any form to be driven accurately. This equipment 
permits driving operations to be carried out manually or automatically 
from the control stand. 

In our experience the alternate clamping of the machine may lead to con¬ 
siderable stressing of the rock formation. A so-called "step-moving" 
effect occurs. This can also be observed in long wall coal mining when 
progressive props are employed. To counteract this, more recent machines 
have other types of prop heads. They enable the pressure to be reduced 
to very low figures. It is difficult to measure this exactly. Practi¬ 
cal results have shown that the "step-moving" effect is largely elimi¬ 
nated by this means. One such machine of this type for soft rock has 
a flat shield which practically consists of single heads of wide area. 

The rates of advance attained to date by such a machine in coal are 


121 


about 33 to 50 ft. in one shift of 8 hours. When coal and soft cuttable 
subsidiary rock occur together, rates of advance of 25 - 30 ft. can be 
obtained in a shift of 8 hours. The consumption of tools for cutting 
loose material in the coal seam is about one pick per 3 ft. 3 in. of 
advance, equivelant to about 30 - 40 DM/meter ($8-11.00/m). This is 
subject to continuous maintenance and checking of the picks. 

In the coal mining industry in West Germany, a method of mining has been 
tested in which longwall mining is employed with the aid of progressive 
props in a downward gradient of 50 degrees. This method of mining en¬ 
courages coal mining engineers to anticipate economic mining of reserves 
of coal which are located in steep seams. This means that driving opera¬ 
tions have to be carried out in seams with downward gradient in which the 
clamped face heading machines are employed. The first results are prob¬ 
ably to be expected in 1971/1972. In the meantime, experience has been 
gained with operation of face-heading machines of shield like design. 

Figure 6 shows the design of a machine which will shortly be delivered. 

It consists of shields which are connected together in telescope fashion. 
The front shield is used for driving, the rear one for clamping. The 
machine is to be employed in a rock formation with a strong tendency to 
expand, but which is nevertheless easily cut. 

Figures 7a and 7b show a quite different version. A face heading machine 
mounted on an excavator is intended to enable very large cross sections 
to be driven, for instance, for underground railway stations. A machine 
such as this can drive a maximum width of 36 ft and a height of 33 ft. 
Simultaneous driving with several face heading jibs mounted on a special 
frame is also conceivable. No experience is as yet available of this. 


Training of Personnel 

Driving with fully-mechanized systems and the forms of organization 
associated with this require detailed training of skilled personnel at 
an early stage. Personnel should, therefore, be intensively trained 
for at least 4 weeks before the machine is used for the first time. 
Particular attention should be paid to the relevant electrical and hy¬ 
draulic systems as well as to the problems involving surveying. 


QUESTIONS OF ECONOMICS 

* • 

Only a few aspects of this extensive and important area are touched 
upon here: 


Capital Investment 

Figure 8 is intended to give a comparison of capital investment costs for 


122 


equipment for driving tunnels with a cross section of about 175 sq. ft. 


Costs 

Driving costs are roughly sub-divided as shown in Figure 9. This shows 
that fixed costs always have to be assumed for the site equipment, etc. 
The variable costs display a logical trend in their relationship, labor, 
tools, power, etc. With high rates of advance, the tool costs rise and 
the cost of power, capital and labor fall. Moreover, in any calculation, 
the indirect costs or savings derived from methods of support resulting 
from the fully-mechanized method of driving should not be disregarded. 

For instance, the circular, smooth excavation permits the use of a sub¬ 
stantially lighter steel or thinner concrete lining. On one site in 
West Germany, for example, the economics of the operation were very 
positively influenced as compared with the older method since, on com¬ 
pletion of driving, the lining with steel pipe and concrete backing was 
placed much more quickly than had been predicted. 

Some specific data may serve to illustrate certain types of cost: 

a) The power consumption is about 15 - 20 kwh/35 cu. ft: 
excavated. 

b) The chisel costs as shown in Figure 2 vary widely de¬ 
pending on the type of rock: between about 5. - 100. - 
marks/35 cu. ft. ($1.40-$28.00/35 cu. ft.). 

c) Depreciation and interest depend on the life. It may 
be theoretically assumed that a tunneling machine has 

a longer life than 5 years. In the case of a hard-rock 
tunneling machine this should be equivelant to a distance 
of about 6 - 12 mi• 

d) The cost of spare parts average about 5% of the new cost 
of the machine per year. 

e) Lubricants and water consumption are very minor param¬ 
eters. 


CONCLUSION 

I have attempted to give you a slight insight into practical experience 
in fully-mechanized tunneling. One could, of course, say a great deal 
more about each of the problems involved. However, I hope I have suc¬ 
ceeded in creating the impression that the dynamic development in tun¬ 
neling in recent years has led to great success and is a practical 
proposition. 

Increasing labor costs and the striving towards a higher standard of 
living and shorter working week will shift the cost limit between the con¬ 
ventional and mechanical methods of tunneling more and more in favor of 
the latter. 


123 


Examples of Headings 


Heading 


Monthly Headway 


Country 


Conventional 


3.435' (1.047 m)/month max. 

average 1.970' (600 m)/month 


CSSR 


fully mechanized 


fully mechanized 


fully mechanized 


fully mechanized 
inclined shaft 


6.550' (2.000 m)/month 

rock of medium strength 

1.000' ( 300 m)/month 

2 

in sandstone (32.200 psi= 2.400 kp/cm ) 
(up till now more than 13.200'= 4.000m) 

426' (130 m)/month 

granite (fine grain sized)-gneis 

48.400 psi= 3.400 kp/cm 2 ) 

440' (135 m)/month 
ingranite (coarse grain sized) 


USA 


Germany 

Harz-mountains 


Sveden 


Switzerland 


Fig. 1 




Cutttr 

enduromce 




%%%//%?% Limtslont, sandy Shalt 
Marl, Shalt 


Diartlt , Sytnitt-and similar 

Sandstone (hard) 

Fig. 2 


12k 












Fig. 3a 






Fig. 3b 



Fig. 3c 



125 















































































































































TVH 54-56 H 
placing of Injection drillings 


d 




rr^f -■ 7? 



:.:i 


I T> v A 



4 



- . —p, 














TVH-General layout 
of Fully-mechamxed tunneling 
mucking by conveyor 



Fig. 5a 


126 











































































































































































































-w-r 


s ecfON 



SECTION 





TVM 

GENERAL 

LAYOUT 

OF FULLY-MECHANIZED 

TUNNELING 

MUCKING 

BY BUNKER 

TRUCKS 




EE 


teKhicaaii 




Fig. 5c 


127 











































































































































































































i 




8 $!*>' r-.* 


Sol 1 Rock Tunneling Machine 

T /P ' TSSM3,85 
VB 12 H 7 




Fig. 6 


Fig. 7a 


Fig. 7b 


128 

































































































































































































Comparison of Capital Investment Costs 


Heading 


Conventional 


fully mechanized 


fully mechanized 


Tunnel Cost 

DM/Ft 


to fit out Tunnel Headings 


Equipment 


Capital Investment Costs 


mucking and site equipment 

approx. 

1.7 

Mio 

DM 

( 490.000 

US 

i) 

Tunneling machine 

approx. 

4.0 

Mio 

DM 

( 1.150.000 

US 

%) 

mucking and site equipment 








soft rock tunneling machine 

approx. 

2.5 

Mio 

DM 

( 715.000 

US 

S) 


with shield 

mucking and site equipment 


Fig. 8 



Overall Average Advance 
Ft/Day 


Rate 

DE MAG 


Fig. 9 


129 







































































































































































































Section 8 


EXPERIENCE IN EDMONTON CANADA WITH EMPHASIS 
ON PNEUMATIC CONVEYANCE OF MUCK 

by 

C. G. Chrysanthou 
Chief Operations Engineer 
City of Edmonton Water and Sanitation 
Edmonton, Alberta, Canada 


Mr. Chrysanthou 
prepared from a 
out the benefit 


died in December, 1970. This paper was 
recording of his oral presentation with- 
of his editorial review. 


131 


EXPERIENCE IN EDMONTON, CANADA, WITH EMPHASIS ON 
PNEUMATIC CONVEYANCE OF MUCK 


The City of Edmonton, the capital of the province of Alberta in Canada, 
is situated on both sides of the North Saskatchewan River. Edmonton 
proper has a population of 460,000 and a surface area of 86 sq. mi. The 
Saskatchewan River in Edmonton varies in width from about 400 ft. to 
about 600 ft. during flood conditions. The variation in level between 
low and high water is about 15 ft., but on the occasions of one or two 
extreme floods it has been 30 ft. The flow at low water is about 1200 
cfs and at average high water 50,000 cfs. The greater part of the City 
lies on a plateau at an elevation 2200 to 2260 ft. above sea level. 

There is from 146 to 206 ft. above the river at low water. 

The City of Edmonton is built upon surficial deposits of variable thick¬ 
ness underlain by Upper Cretaceous strata. The surficial deposits of 
Late Pleistocene age consist of a well sorted pre-glacial sands and 
gravels, glacial till and pro-glacial lake deposits in an ascending order. 
The bedrock of Edmonton is composed of upper cretaceous shales interbed- 
ded with bentonitic shales, sandstone reefs and coal seams. 

During the prewar years the majority of the sewage system discharged 
directly into the river. Only two small treatment plants of very limit¬ 
ed capacity were in operation. With the sudden and rapid growth of the 
City after the war years, it became evident that the two treatment plants 
were too small and could not handle the large increase in sewage flow. 

The concentration of raw sewage in the river got so high that the oxygen 
content of the river was drastically depleted. The conditions got so 
bad that some of the municipalities down stream were unable to use the 
river as a source of domestic water supply. A firm of consulting engi¬ 
neers was retained to study the problem, and commissioned to design a 
sewage system to conform with the new government regulations. 

The fact that the water supply is drawn from the river at a point nearly 
opposite the center of the City affected the general design and made it 
necessary to collect all sewage below this point. The consulting engi¬ 
neer's recommendation was for a major central sewage treatment plant 
with an extensive collection system of interceptor tunnels in lieu of a 
series of small plants located at various locations with a series of 
small lateral collectors. As a result of this recommendation, tunneling 
for interceptor sewers was adopted as a major phase of our sewer con¬ 
struction program. 

All the tunneling to date has been constructed by City forces. We present¬ 
ly have six tunneling crews working with seven tunneling machines. We 
average 5 1/2 mi. of tunnel construction per year in sizes varying from 4 
ft. to 21 ft. in diameter with depths varying from 50 to 180 ft. 

Except for small lateral columns, which are all hand dug, all our tunnel- 


132 


ling excavation is done with tunneling machines or moles as they are 
commonly known in the industry. Our working shafts, are located such 
that a minimum of 3000 ft, of tunnel is excavated from each heading; 
two headings are worked from each shaft. It is an accepted fact that 
the success of any tunneling operation is a direct function of the ma¬ 
terials handling operation. At the last OECD Conference held in 
Washington, D.C., materials handling was placed as a second item in 
priority in the field of research and development. In tunnel sizes of 
10 ft. and upwards this problem is fairly well controlled. The use of 
California switches and other switching devices enables us to excavate 
at a fairly constant rate. It is in the small diameters where the prob¬ 
lems become critical. Fifty per cent of the tunnel excavation is in the 
7 ft. diameter range. It is impossible to install a California switch 
behind the machine for this size of tunnel. The cutting of switching 
stations in hanging wall is an expensive proposition if the run is short. 
Consequently, the only switching of the train is done at the shaft sta¬ 
tion. These limitations cause a considerable loss of excavating time. 
Several time studies of the operation as a whole indicated that the mole 
was operational for only 43% of the time on a 10-hour shift, the balance 
of the time was spent in waiting for the empty trains and installing the 
primary liner. Consequently, a new system of material handling had to 

be implemented to increase the excavating time of the mole. 

0 

At the last symposium on rapid excavation held at Sacramento, Mr. Graham 
Ball ofRadmark Engineering (head offices in Portland, Oregon) presented 
a paper on pneumatic conveyor systems presently used by Consolidated 
Mining & Smelting in Kimberly, British Columbia. The system is used to 
back fill cut and fill slopes. We were impressed with the system and 
we felt that this may be the solution we were looking for. Consequently, 
Radmarkand the City of Edmonton agreed to cooperate to test the Radmark's 
stowing system as a method of removing materials discharged from a tun¬ 
nel ing machine. 

The pneumatic system was chosen because it should greatly increase the 
percentage of time that the tunneling machine can work. As long as a 
pneumatic system is designed to handle the maximum discharge from the 
mole at the maximum conveyance distance, then the mole should work at 
full capacity at all times. By blowing the material directly into a 
truck bin, what I call the back stop on the surface, the regular head- 
frame and hoist can be eliminated. Access shafts can be reduced in 
size. The discharge pipe can be installed into 36 in. diameter holes 
spaced on 800 ft. centers along the route of the tunnel. The access 

holes are needed for the supply of electric power to the mole as well 

as assist In the ventilation of the tunnel. The working area in con¬ 

gested and residential districts is vastly reduced. The pneumatic system 
will also assist in the ventilation of the tunnels. 

The pneumatic system was first installed in a 7 ft. diameter tunnel. Due 
to some difficulties encountered in the installation and operation of the 


133 


system, which I intend to refer to later on in this paper, the system 
was removed and installed in a larger diameter tunnel. The system is 
presently operational behind a 12 ft. tunneling machine. 


The pneumatic system consists of a large volume, low pressure, air blower 
installed in a closed-in trailer positioned at the surface of the shaft 
head. The air is piped to the stowerthrough a 12 in. diameter quick 
coupled pipe. The Radmark feeder or stower is connected to the mole by 
means of a draw bar, A hopper is located directly under the discharge 
conveyor from the mole. Two telescopes have been provided behind the 
stower, one for the air pipe and one for the materials handling pipe to 
permit the blower to travel forward with the mole. When the excavation 
has advanced 10 ft., the telescopes are fully extended and the stower is 
shut down. The telescopes are then retracted, a 10 ft. length of pipe 
is coupled into each line, and the excavation proceeds. The controls 
for the surface blower are located on the stower control panel under¬ 
ground and the over load protection will automatically shut down the 
pneumatic system in the event of any blockages. The materials handling 
pipe is a 10 in, cast iron pipe with an internal surface hardened to a 
hardness of 630 Brinell. An overhead monorail is continually extended 
to supply all the necessary construction materials to the face. 

At this point Mr. Chrysanthou showed a film of the pneumatic system in 
operation. This prompted the following discussion. 


QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION 


What is the maximum size you are striving for there? 

We pass 3 1/2 in. size particles. 

Have you used it long enough to get any idea on pipe cost 
or wear? 

No. 

Why couldn't you drop it into a hopper and blow directly 
out of a hopper? 

Yes, we have done that too. This is basically what you 
have to do when you go into a residential district, you 
can't blow. 

What is the total distance of the pipe from your machine 
to the top? 

About 450 ft. 

What is the maximum that you can go? 

We propose to go 800 ft. laterally and 150 ft. up. 

What is the consumption of the compressed air for 100 cu. 


134 


yds? 

CHRYSANTHOU: I don't think I can give you that detailed information, but 

the blower has a capacity of 5800 cfm at 18 psi. It is 
powered by a 500 hp motor. 

Our comments on the system so far are that the basic idea of the stower 
following the mole is good. The capacity of the pneumatic system is 
adequate and will not restrict the boring rate of the mole. The stower 
is capable of handling 3 1/2 in. material and larger sizes are broken 
down to size by chopping. The equipment can be operated by tunnel labor¬ 
ers. The abrasion factor of the material is low, so pipe and elbow wear 
should not be a problem. Because of the dampness of the material, dust 
is not a problem. 

In the initial installation of the pneumatic system in a 7 ft. diameter 
tunnel, the small diameter of the tunnel compounded v/ith the fact that 
the tunnel was started on a curve caused various inconveniences to creep 
up. The lack of working space make it awkward and frustrating for men 
to work efficiently. The system provided for carrying the telescopes 
behind the stower was designed for straight tunnels. The telescope skid 
could not center itself in the tunnel, therefore, it tended to climb up 
the ribs and not remain under the telescope. Only one ball joint was 
supplied and this was located at the back of the stower. The operators 
had a difficult time lining up pipe joints when a section of the pipe 
was to be added to the telescope. The materials handling pipe was too 
rigid and we had difficulty in forming it to the radius of the tunnel. 

The air pipe could not be located over the material pipe. It, there¬ 
fore, lay on a radius different than that of the material handling pipe. 
Joints in this pipe would get ahead of the joints in the material handl¬ 
ing pipe and, therefore, pipes spools of different lengths were required 
in the air pipe. 

The pneumatic system bogged down when large sizes of material were fed 
to it. The presence of these large pieces could not be avoided and the 
balance of the material bridged in the hopper. This necessitated the 
shutting down of the feeder and manual removal of the bridged material. 

A second set of choppers was installed to break down the large pieces; 
thought it did help some, it was soon discovered that a larger, faster 
and more powerful unit was required in order to keep up with the dis¬ 
charge rate of the mole conveyor. A build-up developed in the elbows. 

As this build-up increased, the operating pressure increased. The back 
pressure was high enough at times to activate the automatic shut-off. 

No cleanouts were provided for the elbows and, since the build-up was 
very high, a lot of time was consumed in dismounting and cleaning the 
el bows. 

The pneumatic system handled the shales and the stiff clay but complete¬ 
ly broke down when a pocket of quicksand was encountered. The water in 


135 


the formation would mix with the clays and turn the clay into a stickey 
mess that would instantly clog the materials handling pipe and the el¬ 
bows. It was at this stage that a decision was made to remove the unit 
and return to the conventional materials handling method. 

You may at this point feel that I have painted a fairly dark picture of 
the pneumatic system. This is not the case. We did not expect any 
miracles from any untried system right off the start. We undertook the 
use of the pneumatic system as a research project. Since it is to my 
knowledge a first of its kind in that particular application, we felt 
that the condition should be presented to you exactly as it happened. 

The system was reinstalled in a 12 ft, diameter tunnel. Our test holes 
indicated that the tunnel would be excavated in a continuous shale for¬ 
mation. Prior to putting the system in operation, the following modifi¬ 
cations were made: 

1, A second ball joint was added to the end of the telescopes. 

This enabled the materials handling pipe to better main¬ 
tain its alignment. 

2. On a curved portion of the tunnel , a five degree miter- 
bend was added at every second joint of the materials 
pipe. 

We are now considering the use of ball joints at every second joint of 
the materials handling pipe. These would be of value even in straight 
tunnels. 

A second telescope will be added to the air pipe line. This could be 
adjusted to keep the flanges of the main telescope side by side. The 
pipe installation procedure would be speeded up by changing both pipes 
at the same time. Mark II type elbows were installed. The elbows are 
fitted with clean-outs for easy access and inspection. The hopper on 
the stower has been enlarged and a more substantial set of choppers in¬ 
stalled. The movie that you saw was after the innovations were put in 
it, except for the chopper. The choppers will be capable of handling 
the large pieces as fast as they are discharged from the mole con¬ 
veyor, thus, drastically eliminating any chances of bridging in the 
hopper. We are also seriously thinking of putting in a vibrating 
grizzly at the top of the hopper that would feed into a small jaw crush¬ 
er attached inside the hopper. This would take care of the large pieces 
of sandstone and hard material. The throat of the stower was enlarged 
to allow larger materials to pass. 

The present application of the pneumatic system is working satisfactor¬ 
ily. Last week we had the best day of the pneumatic system in a 12 ft. 
tunnel. We reached 55 ft. in 20 hrs, in two 10-hour shifts. There 
were quite a few breakdowns and quite a few revisions to be made, but 
it was the best day we made so far. Nevertheless, we still consider it 


136 


to be a research project with room for improvement. There is no 
doubt in our minds that some further changes will be made before we 
are completely satisfied. 

In conclusion, may I say that the pneumatic conveyance system has its 
limitations, in the art of softwork tunneling. It should not be con¬ 
sidered if there is any chance of encountering wet clays or quicksand 
in the course of the excavation. The application of the pneumatic 
system is limited by the diameter of the tunnel. Where switching sys¬ 
tems and double tracks can be installed, the conventional method of 
materials handling is still more economical. In our opinion, the sys¬ 
tem can best be used in a hard rock formation trailing a hard rock 
machine. The pneumatic system is ideally suited for free flowing ma¬ 
terials such as rock cuttings , gravel or sandstone. The nearly uniform 
size of the materials excavated by the hard rock machine would eliminate 
any feeding problems. Though an abrasing problem may develop, the ma¬ 
terial should be more predictable and easier to adapt to. 


QUESTION 


What about the noise on the surface from the blower? 


CHRYSANTHOU: 


The blower is installed in a semi-trailer, a closed-in 
unit, and the walls of the trailer are insulated with 4 
in. fiber-glass bat insulation. Really the noise problem 
is in the range of 75 decibels which is still within 15 
decibels below our noise law. 


QUESTION: 

CHRYSANTHOU: 


QUESTION: 

CHRYSANTHOU 


What about dust at the chopper? 

We have no trouble with dust at the chopper. We have 
dust at the top at the bin after the material has been 
broken down in the pipe during conveyance. 

Is the tunnel pressurized? 

No, we never pressurize. 


QUESTION: Where is the pressure applied? 

CHRYSANTHOU: Well it's fed at the bottom to the stower and the stower 

is, if you can picture it, a paddle wheel rotating at 40 
rpm. The material will drop into it and all the paddle 
wheel will do is feed it into the line where the air is 
coming in from the blower. 


QUESTION: What pressure do you use in there? 

CHRYSANTHOU: Our maximum is 18 psi, but we are working with about 8 

or 9 psi right now. 


137 


QUESTION; 
CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 


Did you investigate other kinds of pipe? 

We entered into a covenant to purchase that material from 
Ragmar Engineering under rental-to-purchase basis. This 
meant that they had the right to set the pipe and the 
equipment on the job. The pipe is made in West Germany. 
It's made by Essen and to date has been an excellent pur¬ 
chase, an excellent choice. 

You mention your best day using this method was 55 ft. How 
does that compare to your normal progress? 

It's about 15 ft. less. 

Have you experimented with the smaller size pipe than the 
10 in.? 

No. This has been our first application. Of course, as 
you know, that the diameter of the pipe is a function of 
the size of the material that you're going to carry through 
it, the velocity its going to travel through it, and the 
air it should take. Ten in. happened to be in our calcu¬ 
lations, the minimum size we could use in this type of ap- 
plication. 

Is the air completely contained from the time it goes in 
till the time it comes back out? 

Yes sir. 

What are the abrasive characteristics of Edmonton formation 
compared, for exampled, to the limestone that we have in 
the Chicago area? 

I don't think it compares. I think that our abrasive fac¬ 
tor is very very low down there with our shales. We have 
never tested it, but we know that the life of our tungsten 
carbite bits is quite high; so really we don't have an 
abrasion problem there at all. 

I'm interested in the comment that you're doing this work 
with about six of your own crews headed by a force account. 

That's a loaded question. What do you mean by force ac¬ 
count? 

In other words, your not bidding the job. 

Well, let's put it this way. We put an estimate in and 
everybody is willing to take a crack at it if he wants to. 


138 


QUESTION: 

CHRYSANTHOU: 


QUESTION: 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 

QUESTION; 

CHRYSANTHOU: 

QUESTION: 

CHRYSANTHOU: 


I think we have a lot of contractors here. To do them 
justice I should explain to them that in 1955, when we 
started initiating this program of sewer construction, 
we set the first tunnel to tender. Of course, not having 
any contractors that were experienced in tunneling in 
Edmonton at the time, they went into joint ventures with 
some of the American contractors. The price was so ex¬ 
orbitant for an 8 ft. diameter tunnel that we felt that 
we could do the job ourselves and write off the capital 
investment against one project, which we did. Then we 
kept on growing and growing till it’s too late to get 
out. But, basically as a member of a form of government 
I'll tell you that my primary interest is to get the 
cheapest price I can get for the City of Edmonton. Now 
whether I do the job, or whether a contractor does it is 
immaterial and irrelevant. As long as he can prove to 
me that he can do it cheaper, more power to him. 

There's another part of this question. What kind of help 
are you using to run the machines? In other words, are 
you using operating engineers, hoisting engineers or la¬ 
borers? 

No. Our system in Canada is a little different than 
yours is. An employee who works for a municipal govern¬ 
ment in Edmonton joins a union that's called the Canadian 
Union of Public Employees. You have your welders, me¬ 
chanics and tunnel diggers, maintenance workers, sewer 
maintenance workers and the fellow that cuts the grass 
in the park. The are all lumped in one union. It makes 
it easier to deal with, a let easier. 

Is there a patent on any of the features of the pneumatic 
system? 

I think that you would have to get in touch with Ragmar 
Engineering in Portland. I couldn't answer that. 

Does the air come from the compressor or a blower? 

The blower. 

What was the removal rate of the material? 

About 200 tons an hour. 

How many miles of tunnel have you dug since 1955? 

I must have about 160 mi. under my belt now. 


139 










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.. 

















































* 







































Section 9 


GEOLOGIC EXPLORATION FOR CHICAGOLAND AND OTHER DEEP ROCK 
TUNNELS TO BE CONSTRUCTED BY MECHANICAL MOLES 

by 

George Heim 
Project Geologist 
Dames & Moore 
1550 Northwest Highway 
Park Ridge, Illinois 60068 

R.W. Mossman 

Assistant Vice President 
& 

Homer W. Lawrence 
Geophysical Section Manager, 

Well-logging Division 
Seismograph Service Corporation 
Tulsa, Oklahoma 


l4.i 





















GEOLOGICAL EXPLORATION FOR THE CHICAGOLAND 
DEEP TUNNEL PROJECT AND OTHER ROCK TUNNELS TO BE 
CONSTRUCTED BY MECHANICAL MOLE 


PURPOSE AND SCOPE 

The Chicagoland Deep Tunnel Project of the Metropolitan Sanitary 
District of Greater Chicago was proposed as a method to reduce 
flooding and pollution caused by the overflow of the combined 
sanitary and storm water sewer system during periods of heavy 
rainfall. The details of the Deep Tunnel Project are discussed 
in the papers included in these proceedings by Keifer, Koelzer, 
and Nei 1. 

In general, as shown in Fig. 1, the Deep Tunnel concept consists 
of interception of the combined sanitary and storm water overflow 
at the overflow points, conveyance of the overflow water in 
tunnels to a mined room and pillar type storage area from which 
the overflow water can be pumped at a reduced rate to permit 
treatment of all waste water. As an added feature, water can 
be stored in a surface reservoir and released to the lower res¬ 
ervoir to provide the capability of peak power generation. 

The purpose of this paper is to describe the subsurface geological 
exploration program performed in 1967 and 1968 for the Chicago¬ 
land Deep Tunnel Project. This program illustrates the type 
and magnitude of exploration performed to demonstrate the technical 
feasibility of the project. 

The Deep Tunnel Project was divided into the Master Plan area 
and the First Construction Zone as shown in Fig. 2. The Master 
Plan Area included the total project area and the First Construction 
Zone was the first area being considered for actual construction. 

The papers by Keifer and Neil present later modification to the 
original construction plan. 


GEOLOGIC CRITERIA 

The geologic criteria required for the Deep Tunnel Project as 
set forth in earlier planning studies included the following: 

1. Rock strata of adequate thickness for the tunnels or 
the mined storage area. 

2. Rock capable of providing long term stability with a 
minimum of supports. 


143 


3. Uniform rock characteristics which are desirable for 
excavation by mechanical moles. 

4. A minimum of water problems from groundwater inflow. 

5. Protection of the groundwater resources from contamination 
which could be caused by outward seepage of the storm 
water from the tunnels or the mined storage reservoir. 


GEOLOGIC SETTING 

The First Construction Zone is located on the east flank of a broad 
structural arch known as the Kankakee Arch. This arch separates 
the Illinois and Michigan structural basins. Because of erosion 
along the crest of the arch, some of the strata present in 
eastern Cook County are absent farther west. The eastward dip 
of the strata on the eastern side of the arch in the Chicagoland 
area is generally 15 to 25 ft. per mile. Superimposed on the 
regional dip are a series of secondary folds whose axes trend 
approximately east-west. 

The substantiated faulting in the Chicagoland area is believed to 
have occurred after the deposition of the Silurian strata. Pre¬ 
viously reported faults include: the Sandwich fault zone, near 
Joliet which trends southeast and has a displacement over 1,000 ft.; 
a complexly faulted area at Des Plaines, Illinois; and several small 
northeast trending faults reported in Chicago Avenue water supply 
tunnel constructed in the late 1920's and early 1930's. In the 
First Construction Zone several faults have been interpreted on 
the maps prepared by Seismograph Service Corporation. 

The strata in the First Construction Zone consists of both soil 
and rock deposits. The soil deposits are made up of artificial 
fill and Pleistocene age deposits of lacustrine clays and sands, 
glacial till, and outwash sands and gravels. The rock strata 
are made up of a thick sequence of Silurian, Ordovician, and 
Cambrian Age sediments consisting of dolomites, shales, and 
sandstones. The deposition of the sedimentary strata was inter¬ 
rupted at various times and several erosional unconformities are 
present. 


SUBSURFACE EXPLORATION PROGRAM 


PURPOSE 

A four phase subsurface exploration program was performed to 
demonstrate the technical feasibility of the Chicagoland Deep 


l44 


Tunnel Project. The exploration program included seismic surveying, 
geophysical borehole logging, test drilling and laboratory testing, 
and groundwater drilling and testing. Seismic surveying and geo¬ 
physical borehole logging were performed in the Master Plan Area 
and all four phases of exploration were performed in the First 
Construction Zone. 


SEISMIC SURVEY 


PURPOSE 

The seismic survey was performed (1) to establish the bedrock 
topography, (2) to establish the configuration of the top of the 
Galena Group, and (3) to locate potential faults. 


SCOPE 

The seismic survey was laid out on a basic 4 mile grid spacing 
in the Master Plan Area and on a basic 2 mile east-west spacing 
and 4 mile north-south spacing in the First Construction Zone. Minor 
modification in the basic layout was made to accomodate variations 
in the city street system and to obtain more detail in subsurface 
information in certain areas. The location of seismic lines is 
shown on Fig. 3. 

Approximately 420 miles of seismic traverses were made during the 
periods of November, 1967 to March, 1968 and May, 1968 to June, 1968. 


FIELD METHODS 

Seismic exploration methods have been used for many years to de¬ 
termine subsurface rock conditions and attitudes. These techniques 
have largely been confined to the search for oil or to measurement 
of the earth's crustal structure on a continental basis. The method 
rarely has been applied to construction problems on a broad scale. 

There are two variations of seismic surveying techniques based 
on physical phenomena common to the physics of wave motion: the 
refraction and reflection methods. Fig. 4 and 5 provide diagrammatic 
illustration of the two diverse techniques. Both utilize a 
controlled source of energy and measure the travel time through 
the rock layers to suitable receptors on the surface. The travel 
times can be converted to depth measurements, and the configuration 
of the surface of a stratum can be interpreted by contouring. 


145 


In the refraction method, travel times are measured for energy 
transmitted through the rock layers for an extended horizontal 
distance as compared to the vertical components of its path. 

In the reflection method, near vertical travel of the energy 
is measured as it is reflected from various subsurface rock layers 
back to the surface. Specific reflective interfaces occur where 
adjacent rock layers exhibit dissimilar acoustic properties. 

In the Chicagoland area, it was desired to map the bedrock surface 
and the attitude and continuity of the deeper Galena-Plattevi11e 
strata. The shallow depths to bedrock, generally less than 150 ft., 
suggested the refraction technique as the most efficient means of 
obtaining the near-surface information. Since the relative acoustic 
velocities made it virtually impossible to secure information from 
the deeper rock layers by refraction means, the reflection method 
was employed for these measurements. 

Because of the intense cultural development in the Chicagoland 
area, the use of explosives for an energy source was not acceptable. 
Therefore, the Vibroseis* method of seismic exploration, which 
has features that particularly adapt it to use in an urban en¬ 
vironment, was selected. The Vibroseis system consists of re¬ 
cording energy from a vibratory source and subsequently applying 
correlation methods to reduce the data to geologically inter¬ 
pretable results. The truck-mounted vibrators (Fig. 6) introduced 
a signal of several seconds duration into the earth. The seismic 
signal has frequency characteristics which vary progressively over 
a predetermined range. Knowledge of the form of this input signal 
enables extraction of the signal from a background of very high 
ambient noise when processing the recorded data. In the Chicago¬ 
land area, random noise of considerable magnitude was generated 
by vehicular traffic and industrial operation. Nevertheless, 
the Vibroseis system permitted operations to be conducted in day¬ 
light hours, with consequent improvement in efficiency. During 
peak traffic conditions, where the presence of the equipment and 
personnel on the principal thoroughfares would have contributed 
to traffic congestion, work was suspended. The Vibroseis signals 
had an additional attribute in that they in no way disturbed 
persons or structures in the vicinity. 

Two Vibroseis field crews were utilized simultaneously to conduct 
most of the investigation. Each field crew was comprised of: 
three truck-mounted vibrator units which operated in synchrony; 
truck-mounted electronic instrumentation for receiving and 
recording the seismic signals; and service vehicles to handle the 


trademark and service mark of the Continental Oil Company 


146 


positioning of individual detectors and their connecting cables, 
for the maintenance of equipment, and for the transportation of 
personnel. Radio communication was maintained between the various 
units involved in the operation. 


DATA PROCESSING 

A flow diagram illustrating the acquisition and processing of 
the seismic data is shown in Fig. 7. The management of the 
operation, the initial processing of the data, and the preliminary 
interpretation of the results were handled from a centrally located 
project headquarters in Elmhurst, Illinois. The individual crew 
offices were maintained in the immediate area of operations and 
were moved from time to time to minimize non-productive travel 
time. Final processing and interpretation of the information 
was done utilizing digital computing equipment and facilities 
at the contractor's plant in Tulsa, Oklahoma. 

Seismic cross sections were prepared in terms of travel time and 
were then subjected to interpretational evaluation to establish 
identification of the geologic horizons represented by the re¬ 
flections, and to determine lithologic continuity and location of 
zones of possible faulting associated therewith. 

The final stage of the interpretive process consisted of con¬ 
version of the various time measurements to depth values and 
the subsequent display of this information on digitally plotted 
depth cross sections and on contoured maps. To perform this con¬ 
version, knowledge of the speed of travel of the energy through 
the various rock layers was necessary. Such velocity information 
was obtained by comparison of the seismic data with geophysical 
borehole information obtained from water wells adjacent to the 
lines of seismic traverse and from deep holes drilled speci¬ 
fically for the Deep Tunnel Project. Direct borehole velocity 
measurements were made in one test hole to provide positive 
confirmation of the identification of the reflecting horizons. 

The velocities established for the various rock units are shown 
on Fig. 8. 


RESULTS 

Good correlation was obtained between the seismic data and the 
horizon tops reported in most of the wells. However, for each 
horizon mapped, the velocity through the overlying material was 
found to vary across the area on a geographic basis. Consequently, 
iso-velocity maps were prepared for each seismic event mapped, 
and each seismic time datum value was converted to a depth re¬ 
lative to sea level according to the appropriate velocity for its 
geographic location, before being placed on the graphic displays. 


1U7 



The results of the seismic survey were presented in the form of con¬ 
tour maps and cross sections. The maps are based on all available 
borehole data and on the calculated seismic depths. They include (1) 
the top of rock, (2) the top of the Galena Group, (3) a partial inter¬ 
pretation cf the top of the Ancell Group, and (4) an isopach map of 
the interval between the top of rock and the top of the Galena Group. 
The top of rock and the top of the Galena were of primary importance 
in this study and the discussion is limited to these surfaces. 

Cross section based on continuous seismic depth calculations were made 
for each seismic traverse. The cross sections show (1) the ground 
surface, (2) the top of rock, (3) the top of the Galena Group, (4) 
the top of the Ancell Group where obtained, and (5) at a few locations, 
the top of an unidentified Cambrian Age formation. 

Top of Rock . The bedrock in the Chicago area is overlain by a variety 
of materials including: man-made fills; glacial deposits of till and 
outwash sands and gravels; and lacustrine deposits of sands, silts and 
cl ays. 

The bedrock surface is the result of a complex geologic history which 
included folding, faulting and erosion. The erosional history had 
the dominant affect on the bedrock surface and, therefore, it is not 
possible to clearly define folds or faults. 

The complexity of the soil deposits which overlie the bedrock, the 
complex nature of the bedrock surface, and the shallow depth of the 
bedrock were major problems which had to be considered in the seismic 
interpretation. The resulting contour maps depicting the bedrock 
topography are believed to present an interpreation with the probable 
error not greater than +10 ft. where the seismic data are recorded. 

Top of Galena . The configuration of the top of the Galena Group is 
the result of folding and faulting. The interpretation of this surface 
in the First Construction Zone is shown on Fig. 9. The accuracy of 
this interpretation is believed to be+25 ft. where the seismic data 
are recorded. The regional dip is to the east, but a series of minor 
folds are superimposed on the regional dip making the Galena surface 
somewhat more complex. 

The seismic data indicates the possibility of nine faults which cut 
the top of the Galena in the First Construction Zone (Fig. 9). The 
calculated displacement along these faults ranges from less than 10 ft. 
to as much as 55 ft. 

Seismic exploration is an indirect method of exploration and the faults 
shown on Fig. 9 have not been substantiated by direct exploration meth¬ 
ods. It is believed, however, that the seismic surveys will detect 
all potential faults having vertical displacements of 20 ft. or more and 
in some instances will detect those with displacements as low as 10 ft. 


l48 




Therefore, the method is valuable to locate potential faults, but their 
actual presence must be substantiated by direct subsurface exploration 
techniques, 


GEOPHYSICAL BOREHOLE LOGGING 


PURPOSE 

The broad purposes of the geophysical borehole logging program were 
twofold: (1) to establish the geophysical characteristics of the 
stratigraphic units and (2) to determine the variations in the rock 
characteristics of each of the stratigraphic units. The logging tools 
selected for use on this project were chosen for specific purposes 
within this broad framework. Loqs were required which would (a) supply 
correlations from hole to hole, (b) define certain rock properties such 
as: porosity, fluid content and movement, and engineering character¬ 
istics such as density and the elastic moduli and, (c) log data which 
would supplement and corroborate the seismic data. 


SCOPE 

A total of 41 boreholes were logged geophysically. Of these, 11 were 
existing wells in the area which were logged to provide a wider distri¬ 
bution of stratigraphic data, 19 were rock holes drilled and cored for 
the Deep Tunnel Project, 10 were ground water test holes drilled, but 
not cored for the Deep Tunnel Project, and 1 soil exploratory hole 
drilled in the upper reservoir area. 


LOGGING TOOLS AND METHODS 

The logging program included the following logs: Gamma Ray, Neutron, 
Formation Density, 3-D Velocity, Temperature and Caliper. 

Gamma Ray Log . Gamma Ray logs measure the natural radioactivity pres¬ 
ent in rocks in fluid-filled and dry holes, whether open or cased. 

Shales normally contain more of the three most commonly occurring 
radioactive elements (uranium,potassium and thorium) than do other 
sedimentary rocks, so the Gamma Ray log may be considered as a shale 
identifying log. Use of the log permits evaluation of the shaliness 
of limestones, dolomites, and sandstones. The Gamma Ray log is sen¬ 
sitive to hole enlargement, the presence of casing and of borehole 
fluid. The effect of all of these conditions, however, can be corrected. 

Neutron Log. The Neutron log measures the amount of hydrogen contained 
in rocks. The hydrogen content is directly related to porosity so the 
Neutron log becomes a porosity measuring device. The Neutron probe 
contains a source which continuously bombards the rock formation 1 with 


149 




a cloud of high energy neutrons. These neutrons collide with nuclei of 
matter in the borehole and surrounding formation and are ultimately 
captured. If they collide with heavy atoms of elements like silicon, 
aluminum, iron, calcium and oxygen, they will be reflected elastically 
without much loss of energy.. If they collide with light hydrogen atoms, 
which have almost the same mass as neutrons, their energy will be 
greatly reduced. When the energy is reduced to a certain level by con¬ 
tinued collisions, the neutron is captured and gamma rays of capture 
are emitted. These gamma rays of capture are measured by a detector 
spaced at a fixed distance from the source. Where hydrogen is confined 
to water present in pores, the Neutron log then measures porosity. 

Shale also contains an abundance of hydrogen as combined water. The 
Gamma Ray log may be used to correct the shale influence on the Neutron 
log. Hole enlargement, casing, or a change in fluid content in the 
borehole will affect the Neutron log, but again, these are all conditions 
for which correction can be made. 

Formation Density Log . The Formation Density log measures the bulk 
density of rock. The probe in this tool contains a gamma ray source 
which continuously emits gamma rays into the borehole wall. The 
emitted rays bounce off electrons and the intensity of the reflected 
rays as seen by a detector in the probe is dependent upon the electron 
density. Electron density is directly proportional to the bulk density 
of all rocks of interest here. The density log is another porosity tool, 
and density is one of the factors used in combination with velocity data 
to compute the elastic moduli. 

3-D Velocity Log . The 3-D Velocity Log measures the transmission time 
of sonic energy in both the congressional and transverse modes through 
the rock surrounding a borehole. The logging probe consists of magne- 
tostrictive transmitter which is pulsed approximately 20 times per 
second as the probe is moved upward in the hole. The pulse energy moves 
outward through the borehole fluid and at the borehole face is refracted 
and travels in the rock media. It is detected as it moves past the re¬ 
ceiver. The various modes of signal travel, which propagate at dif¬ 
ferent velocities, are recorded as a variable intensity display. Fig. 

10 show a ection of a 3-D Velocity log with the pressure, shear, and 
boundai, w e arrivals indicated. 

The 3-D ' 'locity log supplies the basic data for the computation of the 
engineering properties of rocks: bulk, shear, and Young's moduli, and 
Poisson's ratio. Since it measures congressional wave velocity, it is 
also useful in converting seismic survey time data to depths. The 
seismic system is dependent on velocity and/or density changes at which 
reflection of the input energy may occur. The velocity and density 
logs both show graphically the interfaces which should reflect energy. 

The 3-D logger is sensitive to changes in borehole diameter and can 
only be used in fluid-filled holes. 


150 




Temperature Log. The temperature Log measures the temperature in 
fluid-filled and dry holes, and in open or cased holes. The downhole 
probe contains a sensitive, quick-reacting thermistor. Under normal 
increases with depth in accord with the geothermal gradient existing 
in uhe area. When the temperature curve deviates from the normal 
gradient, it indicates a zone in which fluid is entering or leaving 
the hole and the approximate volume of flow. 

Cal iper Log . The Caliper Log is used to supply a record of changes in 
borehole diameter primarily for use in interpreting other logs which 
are sensitive to such changes. There are several types of calipering 
devices, but the most commonly used has 3 pencil-like arms at 120° 
lateral separation. These measuring arms are able to detect small, 
thin changes such as washed out shale laminations. 

All of the foregoing logs are run from a unit as shown in Fig. 11. 
Hoisting equipment and cable reels occupy approximately half the cab 
space, while the other half houses the signal processing equipment and 
recorders. 


RESULTS 

An example of the geophysical borehole logging results is shown in Fig. 
12. The Joliet Formation and the Guttenberg Formation were found to 
be two geophysical marker beds in the Chicago area. The Racine Forma¬ 
tion was found to be a variable dolomite, the Joliet Formation a fair¬ 
ly uniform dolomite, the Kankakee Formation has numerous shale partings, 
the Brainard Formation is a fairly uniform shale, the Fort Atkinson 
Formation is a fairly uniform dolomite, the Scales Formation is a fairly 
uniform shale, and the formations in the Galena and Platteville Groups 
are fairly uniform dolomites. 

Borehole logging results from the cored holes were used (1) to cor¬ 
relate the stratigraphy from cored holes to the previously existing 
boreholes which were geophysically logged during this project, and (2) 
to establish the stratigraphy in the ground water test holes so packers 
could be set to isolate hydrologic units. 


TEST DRILLING 


PURPOSE 

The purpose of the rock core drilling program was (1) to provide cores 
from which the rock characteristics of the various strata could be 
evaluated so the most favorable elvations could be selected, (2) to 
provide positive stratigraphic control in key areas, (3) to provide 
core for correlation with the geophysical borehole logs, and (4) to 


151 




provide boreholes in which the water bearing properties of the rock 
could be evaluated and monitored. 


SCOPE 

Twenty-four core holes with a total footage of 34,360 ft. were drilled 
during the period from November, 1967 to March, 1968. The deepest hole, 
having a total depth of 1,696 ft., was drilled to the upper portion of 
the Eau Claire Formation. 


FIELD METHODS 

All rock core holes were drilled with wireline equipment and excellent 
results were obtained. Water pressure tests were run in all core holes 
to evaluate the water bearing characteristics of the rock strata. All 
the boreholes were instrumented with piezometers to obtain more accurate 
ground water data in the First Construction Zone. 


RESULTS 

Water pressure tests indicated, in general, that the dolomite strata 
under consideration had very low permeabilities and that large water in¬ 
flows into tunnels or into the storage chamber would apparently be 
limited to fractured zones that may be present. 

Excellent correlation was obtained between stratigraphic logging and 
geophysical borehole logging as shown on Fig. 12. 

Laboratory analyses were performed on selected rock samples to establish 
the general range of properties of the various strata. The following 
tests were performed: specific gravity, unconfined compressive strength, 
modulus of elasticity (static and dynamic), drillability, natural water 
content, absorption, abrasion, porosity, permeabi1ity, petrographic 
analyses, x-ray analyses, chemical analyses, wetting and drying, and 
solubility. A partial summary of field and laboratory data is presented 
in Fig. 13. 

The evaluation of the various rock strata based on physical examination, 
geophysical borehole logs, and laboratory analyses indicated the fol¬ 
lowing formations best fulfilled the geologic criteria: Waukesha 
Joltet, Wise Lake, Dunleith, Guttenberg, Nachusa, Grand Detour, and 
Mifflin. 


152 


GROUND WATER DRILLING AND TESTING 


PURPOSE 

A detailed ground water testing program was performed Cl) to determine 
the hydraulic characteristics of the hydrogeologic units shown on Fig. 
14, C2) to determine the feasibility of aquifer protection by artificial 
recharge methods, and (3) to provide ground water observation wells. 

Ten water wells with a total footage of 11,800 ft. were drilled during 
the period from November, 1967 to March, 1968. The wells included one 
deep aquifer test well, three observation wells, and six specific ca¬ 
pacity wells. 


FIELD METHODS 

The water wells were drilled by the cable tool method and the air rotary 
method. After completion of the drilling, each well was geophysically 
logged to establish the stratigraphy so packers could accurately be set 
and the selected hydrogeologic units isolated and tested. A total of 
20 pumping tests and two recharge tests were conducted in the specific 
capacity wells and in the deep aquifer test well. 

Specific Capacity Wells. The Silurian aquifer system and the Galena- 
Platteville hydrogeologic unit were tested in each of the six specific 
capacity wells. Each well was drilled and cased through the overburden 
and then drilled through the Silurian to the top of the Maquoketa. The 
Silurian aquifer system was then pump-tested. After testing, the well 
was drilled to the top of the Galena and cased through the Maquoketa. 
Drilling was then continued to the top of the Glenwood. A packer or a 
concrete plug was set at the Platteville-Glenwood contact and the 
Galena-Platteville unit was pump tested. 

Deep Aquifer Pump Testing . Seven pumping tests were performed in the 
deep aquifer test well. These tests were designed to evaluate the 
Silurian aquifer system, the Cambrian-Ordovician aquifer system, the 
Galena-Platteville hydrogeologic unit, the Glenwood-St. Peter hydro¬ 
geologic unit, the Prairie du Chien-Eminence-Potosi hydrogeologic unit, 
the Franconia hydrogeologic unit, and the Ironton-Galesville hydro¬ 
geologic unit. 

The deep aquifer test well and the observation wells were drilled and 
cased through, the overburden and then drilled through the Silurian to 
the top of the Maquoketa. The Silurian aquifer system was tested and 
the wells were then drilled to the top of the Galena and cased through 
the Maquoketa. The wells were then drilled to the top of the Eau Claire 
Formation at a depth of approximately 1685 ft. Each hydrogeologic unit 
was isolated by inflatable packers and tested individually. 


153 




Recharge Tests . After completion of the deep aquifer pumping test, 
two recharge tests were conducted in the deep aquifer well* Drinking 
quality water was injected into the various hydrogeologic units and the 
build-up of water levels was ohserved in the observation wells. 

The Galena-Platteville hydrogeologic unit was isolated from the under¬ 
lying hydrogeologic units in the two observation welis by means of a 
cement plug. An observation pipe was placed through the cement plug 
in each observation well to permit measurement of the water level in the 
underlying hydrogeologic. units. 

The hydrogeologic units to be recharged were isolated in the deep aquifer 
test well by means of inflatable packers. 

In recharge test 1, water was injected through the Galena-Platteville, 
Glenwood-St. Peter, Prairie du Chien, Eminence, and upper 80 ft. of the 
Potosi as shown in Figure 15 A. Recharge test 1 was continued for a 
period of about 10 days as shown in Figure 15 B. The rate of recharge 
averaged 243 gpm and the build-up in the recharge well was 125 ft. at 
the end of the test. 

In recharge test 2, water was injected through the Galena-Platteville 
and Glenwood-St. Peter hydrogeologic units as shown in Fig. 16 A. Re¬ 
charge test 2 was continued for a period of about four days as shown 
in Fig. 16 B. The rate of recharge was 60 gpm initially, but was de¬ 
creased to 15 gpm because of overflowing of the recharge well. Even 
at the lower recharge rate the well overflowed in four days and the 
test was discontinued. The recharge rate for the four day period av¬ 
eraged 16 gpm. 

The water levels in the two observation wells had not completely re¬ 
covered from test 1 when test 2 was started as shown in Fig. 16 B. 
Complete recovery of the water levels from test 1 was not achieved 
prior to the start of test 2 because of contractual time restrictions. 


RESULTS 

The results of the specific capacity tests are presented in Table 1 
and the results of the deep aquifer pumping tests are presented in Table 
2 . 

Analysis of the recharge test results indicated the following: 

1. The hydraulic characteristics of the St. Peter sandstone 
are too low to permit economical injection rates into this 
unit to develop the necessary ground water mound. 

2. Recharge wells will have to be drilled into the Potosi Forma¬ 
tion to obtain the required hydraulic characteristics to 


154 



develop the ground water mound necessary to protect the aquifer. 

3. Recharge rates during the tests were lower than predicted on 
the basis of pumping test results. This is believed to have 
been caused by (a) chemical composition differences between 
the recharge water and the natural ground water, (b) temperature 
differences between the recharge water and the natural ground 
water, and (c) aeration of the recharge water. 

The aquifer protection system, shown in Fig. 17, consists of maintaining 
a positive ground water head on all unlined structures to insure inward 
seepage rather than leakage of contaminated waters. The water table in 
the Silurian aquifer system is above all tunnels. Fig. 17 shows the 
current (1968) position of the Cambrian-Ordovician water level, the 
future water level without recharge, and the water level with recharge. 

The ground water testing program demonstrated the feasibility of an 
artificial recharge system to protect the ground water resourses in the 
vicinity of the proposed project. 


SUMMARY 

To obtain the most favorable geological condition for deep tunnels to be 
constructed by mechanical moles, the tunnels should be located in struc¬ 
turally sound and uniform rock strata with a minimum of potential ground 
water problems. If the tunnels are designed to be unlined and to carry 
sanitary water, it is necessary to carefully evaluate the ground water 
conditions to assure this valuable resource from becoming contaminated 
by outward seepage from the tunnels. 


155 


SELECTED REFERENCES 


Birdwell Division, 1968, Borehole logging service for the Chicago!and 
Deep Tunnel System for pollution and flood control* 

Harza Engineering Company and Bauer Engineering, Inc*, 1968, Chicago!and 
Deep Tunnel System for pollution and flood control, first construction 
zone, definite project report, appendix G and H. 

Harza Engineering Company and Bauer Engineering, Inc., 1969, The impact 
of the Deep Tunnel Plan on the water resources of northeast Illinois. 

Seismograph Service Corporation, 1968, Report on a Vibroseis Survey for 
the Metropolitan Sanitary District of Greater Chicago, Chicago!and 
Deep Tunnel Plan for pollution and flood control; 

Phase I—mobilization and reconnaissance 
Phase II--first construction zone 
Phase Ill-total combined sewered areas 


156 


CREDIT FOR THE CHICAGOLAND DEEP TUNNEL PROJECT 


Client , . ... The Metropolitan Sanitary District of 

Greater Chicago 
Chicago, Illinois 

Consulting Engineers . . Harza Engineering Company 

Chicago, Illinois 

Bauer Engineering Inc. 

Chicago, Illinois 

Geophysical Exploration. Seismograph Service Corporation 

Tulsa, Oklahoma 

Borehole . Birdwell Division of Seismograph 

Service Corporation 
Tulsa, Oklahoma 

Core Drilling . DiKor - Groves 

Carmi, Illinois 

Layne-Western Company 
Aurora, Illinois 


Ground Water Drilling 
and Testing 


157 





THE DEEP TUNNEL CONCEPT 


Fig. 1 


.158 











































































LockpoM Lock*--^j^' t. 


GENERAL MAP 


Fig. 


159 











































































































INDEX MAP 


l60 


~ig. 3 































































































REFRACTION PROFILE 





161 




















162 










































SEISMIC DATA PROCESSING 
FLOW DIAGRAM 


r^. 

CT> 



163 






































































GENERALIZED STRATIGRAPHIC COLUMN OF THE 
CHICAGOLAND AREA 


Thickness System Series, Group, or Formation 


50'-150' 

150'-300' 
20'-140' 

100'-250' 

170-225' 

100'-150' 

0-80' 

100'-600' 

0-340' 

50'-150' 

90'-220' 

50'-200' 

80'-130' 

10 '- 100 ' 

370-575' 


1200'-2900' 


Quaternary 


Silurian 


Ordovician 


Cambrian 


Precambrian 


Glacial and lake deposits 


Niagaran Series 
Alexandrian Series 

Maquoketa Group 


Galena Group 

Platteville Group 
Glenwood Formation 
St. Peter Formation 
Prairie du Chien Group 
Eminence Formation 
Potosi Formation 
Franconia Formation 

Ironton Formation 
Galesville Formation 


Eau Claire Formation 


Mt. Simon Formation 


Lithology Seismic Velocity 

Sand and clay 2000-8000 ft/sec 


Dolomitic limestone 
Dolomitic limestone 

Shale and dolomite 

Dolomite 

Dolomite 

Sandstone, shale & dolo. 
Sandstone 

Dolomite and Sandstone 

Dolomite 

Dolomite 

Sandstone, dolo. and shale 

Sandstone 

Sandstone 

Shale, dolo. & sandstone 


16,500-19,000 ft/sec 
16,500-19,000 ft/sec 

13,000-15,000 ft/sec 

18,000-19,500 ft/sec 

18,000-19,500 ft/sec 
13,000-18,000 ft/sec 
15,000-17,000 ft/sec 
17,000-18,000 ft/sec 
17,000-18,000 ft/sec 
17,000-18,000 ft/sec 
17,000-18,000 ft/sec 

17,000-18,000 ft/sec 
13,000-16,000 ft/sec 


Sandstone 


Granite 


* Seismic mapping level 


164 


Stratigraphic Column Modified From: 

T.C. Buschbach 
and 

H. B. Willman, Illinois State Geological Survey 


Fig. 8 















































GEOLOGIC STRUCTURE-TOP OF GALENA 
49 HOLES + SEISMIC 


Fig. 9 


165 















































































































































DEPTH 



*- BOUNDARY WAVE 


«- SHEAR WAVE 


0 —TIME 

i— i-*——,— 






Fig. 10 






.166 


li ‘tl'UMItMriMiMiM 




















































































































Fig. 11 


167 









































Fig. 12 


168 


























































































































AQUIFER SYSTEMS 


Fig. 14 


169 

























































OW-2 


GALENA-PUTTEVILLE 


GLENWOOD-ST. PETER 


PRAIRIE DU CHiEN 


8.JL.H 


POTOSI 


OW-I TW-I 


-*»»j - 

>' 


Avg. 243 gpm 
10 days 






RECHARGE TEST NO.l 


Fig. 15 


170 





































































































































A 


OW-2 OW-I TW-I 

- Avg. 16 gpm 


iffr 



4 days 

PLE 1 STOCENE 








SILURIAN 




1 




- 


Mite 

GALENA-PLATTEVt LLE 




| . ... 




GLENWOOD-ST. PETER * 

* ~ 


— 

PRAIRIE DU C.HIEN 


WM 


. eminence 




POTOSI 






RECHARGE TEST NO. 2 


Fig. 


171 



































































































Elevation feet, ,Chicago City Datum 



AQUIFER PROTECTION 


Fig. 17 


172 
























































































































































































































PUMPING TEST INFORMATION - DEEP AQUIFER TEST SITE 



Depth (ft.) 









Hydrogeologic 

Unit Tested 

Top of 
Bottom 
Packer 

Bottom 
of Top 
Packer 

Diame¬ 

ter 

(in. ) 

Pene ■ 

tration 

(ft.) 

Date 

Tested 

Length 
of Test 
(min.) 

Son- 
pumptng 
Le vel 
(ft.) 

Pump¬ 

ing 

Rate 

(gp”i) 

Draw¬ 

down 

(ft.) 

Specific 
Capacity 
(gpm/ft. ) 

Silurian Aquifer 

495.0‘ 

60.0 2 

16 

435.0 

12/11/67 

158 

24 

40 

407.0 

0.098 

Cambrian-Ordovician 
Aquifer 

1684.0* 

614.0 2 

12 

1070.0 

2/14-16/68 

1844 

434 

380 

26.4 

14.400 

Galena-PI at tevil le 

900.0 

614.0 2 

8 

286.0 

2/23/68 

31 

439 

40 

401.0 

0.100 

Glenwood-St. Peter 

1016.9 

919.6 

8 

97.3 

2/19-21/68 

1773 

435 

41 

310.1 

0.132 

Prairie Du Chien, 
Eminence & Potosi 

1366.7 

1116.1 

12 

250.6 

2/25-29/68 

1825 

434 

350 

26.9 

13-020 

Franconia 

1478.6 

1378.7 

12 

99.9 

2/3-5/68 

1841 

434 

300 

237.0 

1.266 

Iron ton-Gales ville 

1684.0* 

1499.6 

12 

184.4 

1/28-30/68 

1808 

434 

300 

100.0 

3.000 

Bottom of well. 

2 Bottom of casing. 
NOTE: TT-1 was the 
for these two tests. 

pumped well 

in all but the Gle 

nwood-St. 

Peter and Galena 

-Plattevi 

lie tests. 

OT-1 was the pumped well 

Table #1 












PUMPING TEST INFORMATION - SPECIFIC CAPACITY TELLS 

Well So. 

Depth 

(ft.) 

Diameter 

(ft.) 

Penetration 

(ft.) 

Date Tested 

Length 
of Test 
(min. ) 

Son pump ing 
Level 
(ft.) 

Pumping 

Rate 

(gpm) 

Drawdown 

(ft.) 

Specific 
Capacity 
(gpm/ ft. ) 





Si lurian 

Tests 





ST-1 

453 

12 

393 

12/6-7/67 

49 

35 

10 

121 

0.083 

ST-2 

550 

12 

475 

12/13/67 

224 

46 

30 

332 

0.090 

ST-3 

426 

12 

381 

1/8/68 

677 

16 

56 

385 

0.145 

ST-4 

549 

12 

457 

1/29-30/68 

629* 

42 

60 

347 

0.173 





1/31-2/1/68 

699 s 





ST-5 

489 

12 

431 

1/22-23/68 

720 

28 

60 

64 

0.938 

ST-6 

533 

12 

460 

2/15-16/68 

721 

46 

30 

357 

0.084 





Galena-Plattevi 

lie Tests 





ST-1 

874 

8 

316 

12/6-7/68 

720 

453 

40 

145 

0.276 

ST-2 

9S9 

8 

294 

1/8-9Z68 

719 

357 

30 

292 

0.103 

ST-3 

913 

8 

319 

1/19-20/68 

721 

433 

50 

267 

0.187 

ST-4 

970 

8 

291 

3/5/68 

56 

395 

30 

411 

0.073 

ST-5 

8S0 

8 

325 

1/30-31/68 

720 

503 

60 

53 

1.132 

ST-6 

9~0 

8 

312 

2/28/68 

45 

431 

40 

398 

0.101 


1 Length of test before acidizing. 

2 Length of test after acidizing. 


Table #2 


























































































Section 10 


THE CONTRACTORS VIEWPOINT OF THE HARD ROCK MECHANICAL MOLE 
WHAT'S CAUSING DOWNTIME? WHAT DO THEY WANT? 


by 


Victor L. Stevens 
Mining Consultant 
821 Kearns Building 
Salt Lake City, Utah 84101 


















CONTRACTOR'S VIEWPOINT OF THE HARD ROCK MECHANICAL MOLE 

WHAT'S CAUSING DOWN TIME? 

WHAT DO THEY WANT? 


I believe the tunnel contractor's greatest dream is to bid a tunnel with 
a mechanical mole, estimating the exact cost and time and when he holes 
through. The permanent lining, if it requires lining, is within one day 
of completion. 

Digressing from the specifics of the subject title, I would like to ap¬ 
proach the problems from the overall concepts of Mechanical Moleing. 

The subject of Mechanical Moleing goes far beyond the machine itself. 

Let us view the subject on the broad concept and break it down into the 
respective components and analyze each part. Mechanical Moleing can be 
broken down into four basic categories, namely: (1) determination of 
ground conditions ahead of moleing; (2) the Mechanical Mole itself; (3) 
muck removal from the tunnel and transportation of men and supplies; 

(4) ground support methods (both temporary and permanent). 

Up to the present time, I believe that determination of ground conditions 
ahead of moleing is the one feature that the tunnel contractor needs the 
most help in to save valuable down time and extremely high costs. In 
so many cases if the contractor knew the conditions ahead of moleing, he 
could take care of the problem prior to the element of surprise. These 
conditions could be fault zones, running ground, water, gas, squeezing 
or heaving ground, just to name a few of the surprises mother nature 
has in store for the underground excavator. 

I would like to show a few examples of ground conditions that were not 
anticipated in a moled tunnel by prior exploration. The first figures 

are of the Oso Tunnel, a part of the San Juan Chama Project in south¬ 

east Colorado. 

Fig. 1 shows a tunnel profile with the bad ground conditions shown in 
a circle. There were nine holes drilled (down to tunnel grade) along 
the tunnel center line prior to bidding. A contractor who bid on the 
job drilled an additional hole in the valley at Sta. 660+50 to check 

for a possible fault. There was not a fault and the formation conform¬ 

ed in dip and strike of the shale bedding with all the other holes. 

The mole was started at the down stream portal and moled into about Sta. 
721+5Q when water, sand, gravel was encountered and caused the back of 
the tunnel to cave in on the head of the mole without any warning. The 
tunnel was then enlarged conventionally to allow for steel spiling to 
be driven over the mole. The mole was then taken out of the tunnel to 
give room for driving conventionally through the bad ground. As soon 
as the mole was out of the tunnel, three diamond drill holes were 
drilled in the face of the tunnel to try to determine the ground con- 


177 


dittons. The holes were drilled 150 ft. long, +15°, - 15°, and level 
and it was found that silt, sand, gravel, boulders and water were 
directly ahead and the conditions bad enough so it was almost impos¬ 
sible to drill any further than the 150 ft. At this point seven holes 
were drilled from the surface and it was determined that there was 1000 
ft. of glacial till to drive through before reaching the shale as orig¬ 
inally expected. 

(Fig. 2] In this case there was a hole at the down stream portal and 
one 3000 ft. from the portal showing the same dip and strike of the 
shale bedding and yet there was 1000 ft. of extremely bad ground in 
between which could not be determined by the drill holes or surface 
examination. If a good seismograph program had been performed prior to 
bidding, this condition would have been determined and remedial action 
could have been taken. The ground could have been grouted or drained 
of water and while this was going on the contractor could have been 
driving the tunnel from the other portal. The 1000 ft. of bad ground 
tunnel could have been driven for $300 to $400/foot of tunnel instead 
of the $1000/foot. 

Fig. 3 shows the extent of the steel spiling to support the ground prior 
to removing the mole. Fig. 4 shows the 6 in. channel spiling as driven 
so as to support the tunnel. Fig. 5 shows the face of the tunnel being 
breast-boarded to keep the face from running prior to and during spiling. 

The second case of surprised ground conditions was at the water-hollow 
tunnel job, a part of the Central Utah Project at Strawberry, Utah. 

There were very few holes drilled on this project and only short holes 
close to the both portals as shown in Fig. 6. There were surface out¬ 
crops of the general formations and from a stratographic standpoint you 
could get a good idea of what ground conditions you might expect. 

There were two potential fault zones that showed up from surface exam¬ 
inations. In the driving of the tunnel, proper precautions were taken 
by putting in steel sets and installing water pumping lines to take 
care of the water. The tunnel was driven through these areas with little 
or no trouble. 

At a point about 3 mi. in from the downstream portal, the tunnel went from 
good ground into an extremely bad fault zone carrying gravel, fault- 
gauge and water up to 1200 gal./min. at very high pressures. The 
length of this fault zone.was 350 ft. long and changed rapidly from one 
type of disturbed ground into another, gouge to conglomerate, to gravel 
to gouge to siltstone, etc. It was necessary to spile more than one- 
half the distance solid with 48# rail, back packed with hay and timber 
to prevent the ground from running and also for support of the heavy 
tunnel arch. The steel channel spiling was driven by means of pneumatic 
spaders. The large 48# rail was driven with the gripper pads of the 
mole itself, this system was very fast and efficient. 


178 



Fig. 7 shows the channel spiling on the tunnel ribs with wooden block¬ 
ing to prevent the ground from running. Fig. 8 shows the 48# rail in 
the back of the tunnel vrith the hay between rails. Fig. 9 shows the 
mole thrust cylinder covered with sand, gravel, gouge prior to clean¬ 
ing up with vacuum car. An extension pipe of 150 ft. long was put on 
the vacuum car and sucked the loose material from around the mole and 
up to the tunnel face. Fig. 10 shows the vacuum car. 

The third case of unexpected ground conditions at the Azotea tunnel 
which is a thirteen-mile tunnel part of the San Juan Chama Project in 
northern New Mexico. The problem in this tunnel was in a 8000 ft. 
stretch in the center of the tunnel. The problem was not a major fault 
itself, but the side effects of a major fault. There were a series of 
displacement or drag effects that appeared tight and undisturbed at the 
time of mole penetration but started to take weight and movement oc- 
cured many months later. If this condition had been known prior to mole¬ 
ing, then the tunnel could have been bored large enough to put in support 
steel. A geophysicist in the area had made determinations from oil well 
drill logs close to the tunnel area prior to the driving of the tunnel 
that showed these conditions would exist but he could not be heard by 
the proper people and gave up. His maps made prior to tunnel driving 
showed almost exactly the problem area. 

I believe all the stated examples could have been determined ahead of 
time with adequate geological and geophysical examination and determin¬ 
ation. If the conditions were determined ahead of moleing the contract¬ 
or would have been better prepared to cope with the problems, saving 
considerable time and money. He could have had the proper tools and sup¬ 
plies on the job for grouting, ground support, water handling, or any 
other proper construction procedures, etc. I believe the oil field 
geophysicists with their exotic means of ground determination in con¬ 
junction with our tunnel geologists can aid and assist the excavator 
in the area of ground determination ahead of moleing. At the present 
time I am informed there are studies going on in California with "sonic" 
methods being used in an active tunnel, to determine ground conditions 
ahead of excavation and a report is to be published early in the coming 
year by the University of California. 

I would like to now pass to the third phase of our tunnel breakdown, 
namely muck removal and transportation. Muck removal in tunnel moleing 
shows the greatest overall delay time. In the case of the Oso tunnel 
where the contractor made as high as 412 ft. in 24 hr,, the mole avail¬ 
ability was only 68% due to muck removal delays in train switching, etc. 
Muck removal means, such as slurry, hydraulic or pneumatic systems, show 
the greatest promise for continuous, fast, efficient muck transportation 
from the tunnel excavation. In conjunction with such systems, means 
must be developed for the transportation of men and supplies 
into and out of the tunnel heading. The method of transportation for 
men and supplies would be directly related to the muck removal system, 
but could be by rail, off-track equipment or mono-rail. 


179 


The fourth phase in tunnel moleing, namely, ground support temporary 
and permanent, Is directly related to the other three phases of tunnel 
moleing. Ground conditions tell us what type of supports will be needed 
and how and when. The moleing rate tells us how and when, and the muck 
removal system tells us how and when. For example, if the ground is 
weak and not self-supporting, then support must be put in around the 
mole at the immediate tunnel heading. If the ground is self-supporting 
then support, if required, can be put in back of the congestion of the 
moleing operation. If a muck removal system is used other than by rail 
transportation, then the permanent lining can be put in with ease in 
conjunction with the moleing progress. The installation of permanent 
lining of the tunnel in conjunction with the moleing operations approach¬ 
es the ultimate in tunnel driving, where permanent lining is required. 

The system was tried at the Azotea tunnel in conjunction with the slurry 
system of muck removal. It was used successfully for 1000 ft. of tunnel 
but had to be abandoned because of continual failures of the slurry sys¬ 
tem. The tunnel was then driven with a Robbins Mole, muck cars and 
temporary support until the tunnel was holed through and the permanent 
lining was installed. (The present methods most generally used for 
ground support at the tunnel face are circular steel ribs with metal or 
wooden lagging and roof bolts with plates, steel lagging or wire mesh.) 

I believe a continuous method of applying gunite or shotcrete at the 
molehead should be developed. This could be done on a rotating arm 
the proper distance from the tunnel rib and advance controlled with the 
advance of the mol e. 

There is also a patent pending for a continuous rolled steel lining 
similar to the method of rolling ventilation pipe, this could be put 
in at the molehead on a continuous basis. 

Now let's consider the second phase.of Mechanical Moleing, the mole it¬ 
self. Contrary to some people's thinking, I believe of the four phases 
of Mechanical Moleing, the moleing phase is presently far ahead of the 
other three. However, there are many improvements to be made in present 
day moles, and I would like to present what I think should be developed. 

There should be two sets of gripper pads, one set in the front and one 
set in the rear. This would allow a choice of positions for gripping 
in case the ground was bad in front and needed support or could not 
properly grip in bad ground. This would also assist in case the mole 
was required to go on a plus or minus grade. A vertical raising or lower¬ 
ing on the gripper pad support could be developed to readily give align¬ 
ment for grade control, this would remove a control pad from the invert 
of the tunnel to allow greater working room. Two sets of gripper pads 
would eliminate intermittent moleing progress because of regripping time. 
Differential and controlled gripping pressures on either side of the 
tunnel gripper pads could be advantageous in variable ground conditions 
and also could aid in guidance control. Differential gripping pressures 


180 


could be advantageous In enlarging the tunnel section to allow for 
passing tracks, switches, or transformer stations, etc., etc. 

The main support beam of the mole should be as small as possible and 
high off the Invert as is possible to give greater working room on the 
tunnel invert. 

Moles should be made to be able to be knocked down into small component 
parts so as to be able to be moved into and out of working faces with 
ease and speed. The access to the molehead should be such that it is 
possible to make rapid changes of cutter bits. 

Lubrication systems should be made automatic or semiautomatic so ser¬ 
vicing can go without mole stoppage. Automatic controls should be put 
on moles, not necessarily to eliminate manpower, but to make for a smooth¬ 
er operation for alignment control and steady penetration rates. 

Rapid changes in line and grade are hard on cutter bits, the molehead, 
the thrust bearing and the main frame itself. 

It would be very advantageous to have the molehead so it could be easily 
expanded from the operator's control cab for tunnel enlargement, this 
was used in some moles with fair success but needs further development. 
Moles should have a longitudinal center opening so that test drilling 
can go on for ground determination independent of the progress of the 
moleing operation. 

It would be advantageous for moles to have a variable speed head rotation 
for maximum efficiency for ground penetration in variable ground condi¬ 
tions. (This lesson can be learned from our oil drilling friends.) 

Moles should be equipped with segmented shields for ground support until 
temporary support can be put in. Each segment of the shield should be 
independently operated, both in and out on radius and back and forth 
along the tunnel line. This would allow the installation of support in 
extremely bad ground. 

Moles should be equipped with vacuum machines to clean the tunnel invert 
to allow the pouring of sub-invert or final invert directly behind the 
mole. 

In conclusion I would like to state the following. I believe there 
should be a standardization in tunnel sizes within certain limitations. 

It seems to me we are defeating the purpose of rapid excavation to have 
to spend such large sums of money for a system to have it outmoded by a 
size change. I would suggest, for example, that with very few excep¬ 
tions all tunnels could be standardized into three sizes: 12 ft., 18 ft. 
and 28 ft., each one of which would have a plus or minus one-foot 
variance. This would allow a contractor a better opportunity to develop 
and amortize a rapid excavation system over many more feet of tunnel to 
the overall financial benefit to the owner. 


l8l 


I believe with some of the aspects I have mentioned, downtime can be 
cut to a minimum and that these are some of the things a tunnel con¬ 
tractor wants and needs. 


182 


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HORiZ SCALE • i.OOO' 



T U N N EL PROFILE 


IS 

BOYLES BROS. DRILLING CO. 

SAIT UK CITY. UTAH 

ONE (1) 

OSO TUNNEL 
CHROMO COLORADO 

FROM JULY 1966 TO SEP67 

AS SHOWN 

d»*i 

4 9 70 





BAD GROUND DETAIL 


I* 


TWO (2) 

OSO TUNNEL 
CHROMO COLORADO 

>OUl 

AS SHOWN 


FROM JULY 1966 TO SEP67 

4 14 70 

•OR 

0-0 M0 


Fig. 2 


183 

































































Fig. 3 



Fig. 4 


Fig. 5 


184 








TUNNEL PROFILE 


J5 


• O T l I » « • O «. DtllLINO CO. 

JAIT l A K f CITY. UTAH 

UT .*> 

ONE (1) 

WATER HOLLOW TUNNEL 
(STRAWBERRY AQUEDUCT) 

FROM NOV. 1968 TO MAR. 1970 

AS SHOWN 

OAtl 

4 15 70 


0—0 HO 


Fig. 6 



Fig. 7 


Fig. 8 


185 













































Fig. 9 



Fig. 10 




186 














Section 11 


RAPID EXCAVATION IN HARD ROCK: 
A STATE-OF-THE-ART REPORT 


by 

Wi11iam E. Bruce 
Supervisory Mining Engineer 
& 

Roger J. Morrell 
Mining Engineer 

Twin Cities Mining Research Center 
Bureau of Mines 

U.S. Department of the Interior 
Minneapolis, Minnesota 


187 








RAPID EXCAVATION IN HARD ROCK— 
A STATE-OF-THE-ART REPORT 


ABSTRACT 

In the United States, 12 tunnels have been machine bored since 1955 in 
rocks of over 20,000 psi compressive strength. One-half of these opera¬ 
tions were performed in a manner superior, in both the speed of boring 
and the quality of the opening, to conventional drill and blast methods. 
The other one-half were either partially successful or failures, and 
the machine had to be replaced by conventional methods. Boring machines 
have been making steady improvement in their ability to bore hard rock, 
and some recent tunnels have been successfully bored in rocks of up to 
30,000 psi compressive strength with maximum advance rates of up to 
1,500 ft./mo. 

This paper describes the evolution of present day tunnel boring tech¬ 
niques. Emphasis is directed toward selected cases from the past 
decade which are discussed in some detail. The data presented has, in 
many cases, been generated by Bureau of Mines personnel during on-site 
studies of the particular job. Wherever feasible, samples of the rocks 
being bored were returned to the Twin Cities Mining Research Center for 
determination of the physical properties. 

This paper presents the significant problems and accomplishments for 
various actual operations. Wherever possible, it presents physical 
characteristics of the rock encountered to aid the audience in evalu¬ 
ating rock hardness. 

Trends for the future are forecast relying on objectives as developed 
by the OECD* as well as on experience of Bureau of Mines personnel who 
for years have followed developments in rapid excavation^ technology. 


INTRODUCTION 

Tunneling by machine is generally classified as hard rock or soft ground 
tunneling. Each classification has unique problems and requires dif¬ 
ferent techniques and equipment. This paper describes the state of the 
art of rapid excavation in hard rock. 


^Organization for Economic Cooperation and Development Advisory Confer¬ 
ence on Tunneling; Washington, D.C., June 22-26, 1970, 

^The term "rapid excavation" is defined in this paper as excavation per¬ 
formed by tunnel boring machines or moles and does not include conven¬ 
tional drill and blast methods. 


189 



To begin the discussion of machine tunneling in hard rock we must first 
define the term "hard rock." This definition must necessarily be 
arbitrary since the ability to fragment rock is a function of both time 
and the fragmentation process. For example, what is considered hard 
rock for today's machines may be considered soft rock in the future; and 
rock which is impossible to break by conventional moles may be readily 
broken by hydraulic processes. 

Considering only present-day machines, however, we would define hard 
rocks as sediments or metasediments (metamorphosed sedimentary rocks) 
with a uniaxial compressive strength greater than 20,000 psi. This 
would include the common varieties of dolomite, limestone, sandstone, 
shale, marble, slate, etc. In the definition of hard rock, we would 
include other metamorphics and igneous rocks with uniaxial compressive 
strength greater than 10,000 psi3. This classification would include 
rocks such as schist, granite and basalt. In addition, we would in¬ 
clude other difficult to mole rocks such as those that are blocky by 
nature, badly fractured in situ, or conglomeritic in nature. Soft rock 
is alternatively defined as sediments or metasediments with uniaxial 
compressive strengths less than 20,000 psi and as other metamorphics 
and igneous rocks of less than 10,000 psi compressive strength. 


DEEP-TUNNEL PROJECTS 

Deep-tunnel projects, such as those being developed in the Metropol¬ 
itan Sanitary District of Greater Chicago (MSDGC), offer many benefits 
to our environment. The combined storm and sewer system includes an 
interceptor network to alleviate flooding of specific urban areas. The 
combined system offers economies because it eliminates construction of 
two separate systems. A combined system may cost only one-third as 
much as a separated system, and the incorporation of hydroelectric pump¬ 
ed storage may contribute income which can reduce the net cost of the 
entire system. 

Additional benefits are realized by a combined storm water and raw- 
sewage system. The combined sewer system is designed to deliver effluent 
of a quality which will meet new stringent standards. The storage capa- 


3 

Note that while the definition of rock hardness was based entirely on 
rock compressive strength, it is well recognized that this parameter is 
not a complete indicator of boreability. There are many researchers, 
including those at the Twin Cities Mining Research Center, who are try¬ 
ing to develop an accurate, universally accepted boreability index. 

Until one is developed, however, rock compressive strength will remain 
as the one common parameter recognized by the entire tunneling community 
as being related to boreability. 


190 



city is a safety valve to elminate problems of sewage overflow during 
periods of high rainfall. 

The smoothing out of the power supply-demand curve by the use of pumped 
storage offers advantages. Because power can be generated to meet 
high demands using release of surface water to underground storage, 
customer needs may thus be met without the atmospheric pollution associ¬ 
ated with some coal burning plants. 

Finally, if water table recharge by injection wells is incorporated, 
ground water levels, which historically have been falling, could be 
maintained at desirable levels. All these advantages are in line with 
the desperate need of a society intent on improving its environment. 

Public officials equating the advantages of environmental and safety 
improvements with fiscal and budgetary constraints are necessarily sen¬ 
sitive to cost factors including excavation costs. 

Rapid excavation in hard rock holds promise for diminishing project 
costs; however, such excavation is sensitive to the laws of supply and 
demand. We are all aware of the pace of excavation needed to provide 
efficient services demanded by the public. Advances in fragmenting 
hard rock are needed now to provide high-speed underground transportation, 
efficient underground emplacement of utilities, and economical develop¬ 
ment and production of the Nation's mineral reserves. Our future 
needs will be even more demanding. 


TUNNEL BORING - PAST AND PRESENT 

Although tunnel boring machines have evolved over the last century, 
the 1950's saw the first extensive use of mechanical moles. 

The early successes were achieved with Robbins boring machines in 
the tunnels of the Missouri River Basin in the 1950's. The rocks 
encountered, although bored successfully, might well be considered 
to be very soft sedimentary rocks, probably in the 5,000 _ to 10,000- 
psi range. 

The dawn of present-day tunnel boring probably occured in the 1960's. 
During the sixties, noteworthy advances were made, but not without 
equally spectacular failures. 

Before beginning a discussion of tunnel boring in hard rocks, we will 
summarize the results achieved during the sixties in what we have 
defined as soft rocks. Although this brief discussion will make no 
mention of earth-boring ventures, it should be remembered that many 
earth-boring jobs have been undertaken during the past two decades. 

In 1961, a Robbins machine operated with limited success in the Kerr- 
McGee Corp. Section 33 mine near Grants, New Mexico, in sandstone 


191 


ranging from 1,200-to 2,500-psi, Here progress was limited both by 
adverse water conditions and by rock too soft to withstand forces re¬ 
quired to anchor the mole. In 1961, a Robbins machine bored 8,000-to 
15,000-psi material in the Homer-Wauseca mine in Upper Michigan with 
limited success, primarily because of directional control problems and 
adverse water conditions. Another project in 1963 involved two Hughes 
machines and one Robbins machine boring an Arizona water-diversion 
tunnel for the Phelps Dodge Corp. Success on this particular job was 
also limited by water problems as well as guidance problems. The ma¬ 
terial involved was sandstone ranging from 2,000-to 15,000-psi. Guidance 
problems on many tunnel boring jobs led to introduction of the laser for 
improved directional control of boring machines in the mid-sixties. In 
1965, in the Navajo No. 1 tunnel in New Mexico, the Hughes Betti I ma¬ 
chine, using a sophisticated laser guidance system, successfully bored 
a tunnel in 5,000-to 10,000-psi sandstone and deviated less than 5/8 in. 
along the entire tunnel. Starting in 1965, Jarva machines operating in 
St. Louis successfully bored sewer tunnel in limestone ranging in com¬ 
pressive strength from about 15,000-to 20,000-psi. At approximately the 
same time, 1965 through 1967, Robbins moles successfully bored tunnels 
in shales with strengths up to 10,000 psi at the San Juan-Chama project 
in northern New Mexico and southern Colorado. The San Juan-Chama pro¬ 
ject, consisting of three tunnels, set a record by boring about 420 ft. 
during one 24-hr. period. This spectacular achievement was made in 
the Oso tunnel which was also the site of a rather classical case of 
changed conditions. Prospect holes spaced at about 1,000-ft. intervals 
failed to delineate a zone of about 900 ft. of loosely cemented con¬ 
glomerate which forced a temporary cessation of machine tunneling. 

In 1967, a Calweld boring machine successfully bored a storm sewer in 
the St. Peter sandstone underlying Minneapolis. The sandstone has a 
uniaxial compressive strength less than 500 psi. Although the machine 
performed successfully, an inrush of water occured shortly after boring 
was completed, with the result that the machine was buried in debris for 
several months. 

So far, we have mentioned but a few tunnel boring operations carried 
out during the past decade. We have reserved discussion of those opera¬ 
tions which took place in what we have defined as "hard rock." These 
cases are reserved for the main topic of discussion of this paper. 


THE STATE OF THE ART OF HARD ROCK BORING 

A typical U.S. manufactured hard rock mole can be described as a self- 
advancing rotary drilling machine which cuts the full face of the tun¬ 
nel in a semicontinuous fashion. Most machines consist of an inner and 
an outer frame. The inner frame of the mole usually carries the cutter- 
head which both rotates and advances forward as drilling proceeds. The 
outer frame is kept stationary during the cutting process by means of 
large hydraulic jacks which are forced out against the tunnel walls. 


192 


From this stable position, the thrust and torque of the cutterhead are 
reacted. The cutterhead is fitted with a number of individual cutters 
which cut or spall the rock as the cutterhead is rotated and forced 
against the tunnel face. The cuttings are collected by buckets behind 
the cutterhead and are discharged onto a conveyor which carries them 
to the muck haulage system behind the machine. To illustrate some of 
these features a Jarva Mole is shown in Figure 1. 


BASIC CYCLE 

The basic operating cycle (Figure 2) of a typical boring machine is as 
follows: 1) To begin the stroke, the mole is aligned in the desired 
direction of advance by the rib jacks which shift the axis of the mole 
in the desired direction. These rib jacks also serve to lock the machine 
securely in the tunnel when boring. 2) Boring proceeds as the thrust 
cylinders force the rotating cutterhead into the tunnel face. The 
torque and thrust of the cutterhead are resisted through the mole by 
the rib jacks. 3) At the end of the forward stroke of the thrust cylin¬ 
der, the rib jacks are released, the support jacks are lowered, and the 
machine is moved ahead by retracting the thrust cylinder. 4) The mole 
is again aligned in the tunnel and is ready to bore another stroke. 


BASIC OPERATIONS IN HARD ROCK TUNNEL BORING 
Rock Disintegration 

The rock disintegration system of a tunnel boring machine is composed 
of the cutterhead and the individual cutters mounted upon it. All hard 
rock machines manufactured in the U.S. use some type of rolling cutters 
which are usually hard-faced at selected spots with tungsten carbide or 
which have sintered tungsten carbide inserts on the cutting surfaces. 

The most popular cutters are either single or multiple disks with 
tungsten carbide inserts on the periphery, or roller-shaped button bits 
which have tungsten carbide inserts mounted around the entire surface 
(Figure 3). The button bit is used in the hardest rocks where the rock 
will not break out readily between two adjacent kerfs. The single or 
multiple disks are used in hard rock where chipping between adjacent 
disks is possible and thus give a larger chip product and usually fas¬ 
ter penetration. Most cutters have replaceable cutter shells and bear¬ 
ings so that, depending on which fails first, either the bearings or 
cutter surfaces can be replaced separately. 

Depending on the type of machine, the center section of the main cutter¬ 
head can revolve either with the main cutterhead or independently. If 
the center of the cutterhead revolves independently, it is usually 
equipped with a tricone type cutter and rotated at a speed of 30 to 60 
rpm. Usual practice is to use a thrust of 50,000 lb./ft. of cutter¬ 
head diameter and to use a rotary speed equal to 90 divided by the di- 


193 


ameter in feet. The larger the cutterhead diameter, therefore, the 
slower it is revolved; the speed of the outside cutters is thus held 
at an acceptable level. The majority of the hard rock moles described 
in this report had a rotary speed of 8 to 9 rpm, a maximum thrust 
capability of between 1 and 1-1/2 million lb., and a maximum torque 
capability of between 300,000 and 500,000 ft. lb. 


Materials Handling 

i 

After the rock is broken from the tunnel face, it falls to the invert 
of the tunnel where it is removed by buckets mounted behind the cutter- 
head. As the cutterhead rotates, these buckets scoop up the broken 
material from the invert and deposit it on the machine conveyor. This 
is a belt conveyor, usually 24 in. wide, which carries the muck to the 
end of the machine and, in the majority of cases studied, onto a trail¬ 
ing conveyor. The trailing conveyor, which advances along with the mole, 
is 20 to 30 in. wide and 200 to 300 ft. long and carries the muck from 
the mole to the muck cars. Except for the White Pine machine, which 
used conveyor haulage, all the machines studied in this report used 
train haulage. The locomotive type and size varied as did the muck cars. 
Most operations used a California switch to pass the empty and loaded 
trains in the tunnel. The muck trains on the return trip generally 
carry supplies, such as cutters or support materials, back into the tun¬ 
nel . 


Primary Support 

In hard rock boring, where the rock is not excessively fractured, pri¬ 
mary tunnel support requirements are usually minimal. The very nature 
of machine boring is such as to create a minimum disturbance to rock 
outside the tunnel walls. The result is a stable opening which re¬ 
quires fewer and lighter supports. Of the tunnels studied in this re¬ 
port, over one-half required little or no support. Except for one tun¬ 
nel in blocky ground, the rest required only minor roof bolting or 
shotcreting to control the tunnel roof. In two of the MSDGC sewer tun¬ 
nels in Chicago (Jobs 8 and 9) the bored tunnel surfaces were of such 
high quality that the final concrete lining was eliminated. Blocky 
ground and occasional rock falls or water inflows from fault zones, 
solution cavities, etc., still present problems in hard rock tunnels. 
Therefore, many hard rock machines have both partial shields around the 
top of the machine to protect them from these hazards and roof pinning 
drills for the installation of roof bolts and mats for temporary sup¬ 
port. All machines can be equipped with mechanical aids for setting 
ring beam supports if greater support is necessary. 


19^ 


Survey and Control 

TKe maintenance of line and grade lias become routine In recent years 
with the use of the low power, continuous output laser which can project 
a thin beam of visible light for long distances. In a typical Installa¬ 
tion the laser is set up on the tunnel rib some hundreds of feet behind 
the tunneler by conventional surveying methods. A reference beam on the 
correct line and grade is then projected toward the mole where it strikes 
two targets mounted at the front and rear of the machine. To keep the 
mole on course, the machine is shifted to keep the beam centered on 
these targets. In recent years many of these targets have been built 
with photoelectric cells which are activated when hit by the laser beam. 
These photoelectric cells provide a continuous readout of the mole's 
attitude in the tunnel and can also be used to signal a servocontrol 
system to automatically adjust the mole to keep it on proper course. 

Most of the newer tunnel boring machines studied in this report used 
laser guidance systems. 


Environmental Control 

Dust generation has been one of the most serious environmental problems 
associated with tunnel boring machines. This problem has been most 
successfully solved by two methods, used either singly or in combination. 
One method is to use water sprays near the cutters to reduce the airborne 
dust. Controlling the water to these sprays is critical, however, as 
too much water will make a slurry of the cuttings while too little 
causes the cuttings to become too sticky to handle. The other method is 
to isolate the cutterhead with a flexible shroud and evacuate the dust¬ 
laden air from this area with a vacuum system. This air can then be run 
through a wet scrubber or exhausted directly from the tunnel. 


CASE HISTORIES 

Using our definition of hard rock, the entire U.S. experience in this 
field reduces to 12 jobs. Approximately one-fourth of these jobs were 
definitely not successful; i.e., the machines could not bore the rock 
and had to be removed. Another one-fourth were partially successful; 
i.e., they could bore the rock, but very slowly. The other one-half 
were considered very successful; i.e., the penetration rate, quality of 
the opening, and sometimes the cost, were superior to what could have 
been accomplished by conventional methods. 

The jobs we will be describing are presented in chronological order, 
with the earliest being discussed first. Since most of these had 
similar muck handling, guidance, and environmental control systems, 
these will not be discussed in detail. A summary of all pertinent tun¬ 
nel data and boring machine data for each job is given in tables 1 and 
2 at the end of this report. 


195 


The four companies now manufacturing hard rock tunnel-boring machines 
in the U.S. are Jarva, Lawrence, Robbins and Calweld. Each of these 
companies has manufactured successful hard rock machines. Other U.S. 
firms manufacturing tunnel-boring machines, but whose machines have not 
been used in what we have defined as hard rock, are the Hughes Tool 
Company the Mining Equipment Manufacturing Company (MEMCO) and Dresser 
OME. 

The first hard, rock tunnel bored in the U.S., by our definition, was in 
Chicago, in 1956. The project was a 9-ft.-diam sewer tunnel constructed 
in limestone with a compressive strength of 18,000-to 25,000-psi. Al¬ 
though information on this job is scarce, we assume that the rock was 
the same kind as that in which the present day Chicago sewers are being 
constructed. 

The mole used on this job was a Robbins model 103 and the fifth one built 
by that company. At 17 tons, this was a light machine by today's stan¬ 
dards. The cutterhead was fitted with both disk and drag cutters. This 
machine had a thrust of only 110,000 lb. but had a torque of 138,000 ft. 
lb. This high torque to thrust ratio was probably made necessary by 
the drag cutters which require a large tangential force to move them a- 
cross a rock surface. 

Although the mole achieved an average penetration rate of from 2 to 4 
fph, it was not successful because the drag cutters were unsuited to 
the hard limestone. The carbide inserts in these cutters were hard 
enough to cut the rock, but the bits suffered from excessive shock load¬ 
ing and the inserts could not be kept in their tools. The replacement 
of these inserts was a major source of downtime and expense (9). 4 

Experience gained on this job led to the successful boring of a similar 
sewer tunnel in Toronto, Canada, the next year. This mole, also a 
Robbins machine, was modified to increase the structural strength, as 
well as the torque and thrust capabilities. Probably most important, 
the drag cutters were replaced with rolling disk cutters. This machine 
achieved advance rates of over 100 fpd. 


Job No. 2 

The next hard rock tunnel was the Richmond water tunnel begun in 1964. 
This 12-ft.-diam., 5-mi.-long tunnel was designed to bring 300 million 
gallons of water daily from Brooklyn to Staten Island. 


^Underlined numbers in parentheses refer to itmes in the list of refer¬ 
ences at the end of this report. 


196 



The rock bored was the Manhattan schist which is composed primarily 
of quartz with small amounts of feldspar, garnet and muscovite. With 
a compressive strength of 25,000 psi, this was the hardest rock attempted 
by a tunnel borer up to that time. 

The mole used on this job was the prototype Alkirk Hard Rock Tunneler, 
model HRT-12, built by Lawrence Manufacturing Co. (Figure 4). This mole 
uses the pilot-pull principle. In operation a 17-1/2-in-diam pilot hole 
is bored some 9 ft. ahead of the main cutterhead. A gripper and rubber 
packer are then expanded to anchor the pilot drill assembly in the hole, 
and the hydraulic unit pulls the cutterhead against the face to provide 
a portion of the total thrust generated by the machine. The balance of 
the thrust is generated by a conventional rib jack and thrust cylinder 
arrangement. This pilot drill, in addition to providing thrust, also 
serves to keep the mole on course and provides additional stability 
while boring. The main cutterhead was dressed with 53 tungsten carbide 
button bits and revolved at 9 rpm. The machine had a thrust of 1 
mil Ion lb. and a torque of 250,000 ft. lb. The estimated cost of this 
machine was $500,000, but it was expected to pay for itself from the 
reduction in concrete used in the lining because of reduced overbreak. 

Although the mole achieved an average penetration rate of 4 fph when 
in operation, it was hampered by machine as well as geological problems 
for most of the year and required continual adjustment. Just as the 
machine was becoming debugged, the cutters failed to perform satis¬ 
factorily. Finally, after one year of effort had achieved only 200 ft. 
of tunnel, the mole was pulled off the job and the tunnel was finished 
by conventional drill and blast methods. 

Despite these difficulties, this machine showed that rock as hard as 
25,000 psi could be bored at satisfactory rates of advance with a 
mechanical mole. 


Job. No. 3 

The first hard rock boring success in the U.S. took place at the Re¬ 
public Steel Corp. Adirondack Mine at Mineville, N.Y., in April 1967. 
The project was a lO-ft.-diam. inclined shaft, 765 ft. long and with 
a slope of 27 degrees. 

The rocks encountered on this bore ranged from magnetite ore with a 
compressive strength of 10,000 psi through horneblende, biotite gneiss, 
and gray granite gneiss. This last rock has a compressive strength of 
35,000 psi. 

The mole used was a Jarva Mark 11 equipped with tungsten carbide button 
and kerf cutters (Figure 5). The penetration rate ranged from 1 to 4 
fph and averaged 1.67 fph. 


197 




Although the penetration rate was low and the length of the bore was 
short, this was the first success in hard rock boring in the U. S. The 
other noteworthy feature of this job was the ability of the machine to 
bore on a 27-degree downgrade 


Job No. 4 

Job No. 4, the Lawrence Avenue Sewer tunnel (Figure. 6), is being bored 
in Chicago, Ill. This job began in March 1968 and as of September 1970, 
6,760 ft. of 13-ft 8-in.-diam. tunnel and 3,968 ft. of 13-ft. 4-in.-diam 
tunnel had been bored. 

The rock being bored is the Niagaran dolomite, a massive, competent, 
and dry rock. Our tests at the TCMRC show this rock to have a compres¬ 
sive strength of from 17,000-to 32,000-psi with an average of 27,000 psi 

The first 7,000 ft. of this tunnel was bored with the prototype Alkirk 
Miner, the same as was used in the previously mentioned Richmond Water 
Tunnel. At the beninning of this project, a number of difficulties 
were experienced with this machine including an electrical fire. During 
the last 4 months the machine averaged an impressive 1,000 ft./month. 

In December 1969, a new Lawrence machine was installed, and by July 1970 
it had completed 4,000 ft. of tunnel known as the Harding Avenue Section 
The machine is now working on the remaining 12,670 ft. of the Lawrence 
Avenue job. 

This second mole has achieved some excellent boring rates, as have the 
other two moles working in the Niagaran dolomite (Jobs 8 and 9). Thus, 
where conditions are right, even in rock which is quite hard, the exca¬ 
vation rate of tunnel moles has shown steady improvement and holds even 
greater potential for the future, primarily because of its continuous 
fragmentation system. 


Job No. 5 

One of the most successful machine-bored hard rock tunnels began in 
September 1968 and was completed 9 months later. This was the 20,000 ft 
long River Mountains tunnel driven by Utah Construction and Mining Co. 
with a Jarva mole. This 12-ft.-diam tunnel through the River Mountains 
was part of the Southern Nevada Water Project, which is designed to 
bring water from Lake Mead to Las Vegas and other southern Nevada cities 

The rocks encountered along this bore were primarily extrusive volcanic 
rocks of an extremely complex and variable geology, mainly tuffs and 
breccias, rhyolite, and rhyodacite. The rhyolites had compressive 
strengths of from 3,000-to 10,000-psi and the rhyodacites from 4,000-to 
23,000-psi. Over 40 fault zones were crossed during this bore and, 


19 8 


except for some blocky ground at these faults, they did not present any 
great problems. Furthermore, the tunnel was dry along its entire length. 
The combination of fairly soft but competent rock and dry conditions 
offered nearly perfect conditions for a tunnel boring machine. 

The mole used on this project was a Jarva Mark 11-1200 (Figure 7) with 
a thrust of 620,000 lb. and a torque of 170,000 ft. lb. The cutterhead 
was equipped with 30 cutters and rotated at 9.2 rpm. In the hard 
rhyolites and rhyodacites, the four gage positions were equipped with 
tungsten carbide kerf cutters. The interior cutters were of steel, 
either milled tooth or disk type. The fact that the steel cutters could 
be used indicates that the majority of the rock must have been fairly 
soft. Cutter cost averaged less than $15/1ineal ft. of tunnel ($3.60/ 
cu. yd.), but on stretches where hard rock was unexpectedly encountered, 
the soft cutters lasted for only a few feet and raised the cutter cost 
to $40/ft. ($9.50/cu. yd.) (8). 

The penetration rates on this job varied widely because of the different 
rock types encountered. In the hard rhyodacites the penetration averaged 
2 fph, and in the softer tuffs it averaged 23 fph. The average penetra¬ 
tion per shift was 33 ft. and per day 110 ft. 

The River Mountains tunnel was completed on schedule and cost $90/1ineal 
ft. ($21.20/cu. yd.), an estimated savings of $50/ft. over conventional 
methods (8). This project demonstrates that in a job of reasonable 
diameter and length and in favorable conditions (i.e., in dry, fairly 
soft but competent rock, even if very hard in sections) a tunnel boring 
machine connot be matched for speed or quality of the opening, by con¬ 
ventional excavation methods. 


Job No. 6 

Probably one of the most difficult tunnel boring projects in the U.S. 
was in the Heel a Mining Co. Star Mine at Wallace, Idaho. This job 
began in November 1968 and was discontinued a year later after boring 
only 437 ft. of tunnel. 

The excavation was carried out in the Revette Quartzite Formation, a 
hard, brittle, thickly bedded rock with a high silica content. The 
rock is very abrasive and tends to be badly fractured along a series 
of fracture plane systems. The compressive strength of this rock ranges 
from 10,000-to 51 ,000-psi with an average of 29,000 psi. 

While this kind of hard rock was generally not considered economically 
boreable, data accumulated during the operation of raise boring equip¬ 
ment at the mine indicated an acceptable cutter life and penetration 
rate for a successful boring operation. The machine manufacturer in¬ 
dicated that a penetration rate of 2 to 3.5 fph might be expected (3_). 


199 



The 9-ft.~diam. Jarva mole used on this job was a small machine with 
a weight of 30 tons and a correspondingly low thrust and torque of 
560,000 lb. and 132,000 ft. lb. respectively. The cutterhead was 
equipped entirely with tungsten carbide studded cutters. 

This mole achieved an average penetration rate of 3.5 fph with a max¬ 
imum rate of 8 fph. However, due to extensive modification of the mole, 
coupled with a long supply route, the mole had a very low availability. 

The major difficulty on this job was the coarse character of the rock 
cuttings. Much of the muck consisted of 6-to 9-in. pieces produced by 
failure of the rock along existing fracture planes. These large pieces 
damaged the cutters, muck buckets, and drive train of the mole. To re¬ 
duce the size of this muck, a false face was installed on the cutter- 
wheel to keep the large blocks from falling from the face until they 
could be broken up by subsequent cutter passes. When this attachment 
did not work, the decision was made to modify the machine to handle the 
large muck (3j. These modifications were partially successful but did 
not solve another serious and costly problem, the failure of the cutters 
and cutter bearings. 

The bearing seals on the cutters would first deteriorate, which would 
allow the abrasive quartzite dust to enter the cutter bearings, causing 
them to fail. The gage cutters which had to pass through the muck at 
the invert had the shortest life of all and were replaced three times 
more often than the interior cutters. Another possible reason for the 
short life of the gage cutters is that the gage section of the hole 
(outer edge) requires more energy to cut than do the other sections of 
the hole. This is true of any tunnel boring job. 

The inability of the mole to bore this ground was due to the combination 
of blocky and abrasive rock which represents the worst of conditions for 
a tunnel boring machine. 

It is interesting to note that the problem of the falling rock occurred 
only at the face of the tunnel, and once a section was bored the opening 
was stable and did not require any support. 


Job No. 7 

The largest hard rock mole built in the U.S. in terms of weight, horse¬ 
power, and cutterhead diameter, was the wel1-publicized White Pine ma¬ 
chine manufactured by James S. Robbins Co. (Figure 8). This 260-ton, 
1,700-hp, 19-ft.-diam. mole is currently being used to drive development 
openings in the White Pine Mine, White Pine, Mi. The first such open¬ 
ing is a 9,000-ft.-long development drift which will connect the No. 3 
shaft to the mining front. 

This drift is being bored through the Copper Harbor formation which lies 


200 


beneath the ore horizon. This formation is a moderately wet massive 
sandstone, with an average compressive strength of 25,000 psi and a 
peak strength of 31,000 psi. 

During the shakedown period, a number of modifications were made on this 
machine. The double-rotating cutterhead was converted to a single-ro¬ 
tating system turning at 4.5 rpm. The center tricone cutter, which 
failed because of the low rotational speed, was redesigned to rotate in¬ 
dependently of the main cutterhead and at a much faster speed. The 
original roof pinner drills were replaced with pneumatic drills when 
they failed to achieve satisfactory penetration rates. Many changes 
have also been made in the arrangement of the individual disk cutters 
on the cutterhead. 

A conveyor was used for muck haulage on this job. The usual trailing 
conveyor behind the mole discharged into an extendable, cable-supported, 
36-in-wide haulage conveyor. This conveyor was hung by adjustable 
chains from 6-in. channel sets bolted on 4-ft. centers on the top of 
the tunnel. 

This job began in November 1968, and as of July 1969, 961 ft. of tun¬ 
nel had been bored in 373 hours of actual machine operation. The 
average penetration rate was 2.6 fph. Total cost per foot of tunnel , 
including labor, electric power, cutters, other materials, and de¬ 
preciation, averaged $125. Cutter costs averaged $30/ft. excluding 
the first 290 ft. of tunnel { 2 ). 

The latest progress reports show that as of November 1970 the machine 
had completed a total of 2,000 ft. of tunnel at a progress rate of 200 
to 300 ft./month. 


Job No. 8 

The next tunnel is known as the Calumet Intercepter Sewer 18-E and is 
part of the MSDGC's deep tunnel plan for Chicago, Ill. This plan com¬ 
bines storm and sanitary sewer systems and power generation facilities 
into one large network. Essentially the combined sewer system is de¬ 
signed so that in periods of storm runoff the mixture of raw sewage and 
storm water is stored in underground chambers instead of being released 
untreated into the environment. 

The Calumet tunnel is 18,000 ft. long and 16 ft. 10 in. in diameter. 
This job began in April 1969 and 16,000 ft. had been completed in 
September 1970. The rock being bored is the Niagaran dolomite with a 
compressive strength of 17,000-to 28,000-psi. 

i 

The Jarva Mark 21 mole being used on this job (Figure 9) has a thrust 
of 2,100,000 lb. (the largest thrust of any hard rock mole to date) and 
a torque of 890,000 ft. lb. The cutterhead was equipped with tungsten 


201 



carbide insert disk cutters. 

This mole achieved an average penetration rate of 6 fph and an average 
footage per shift of 27 ft. The availability of this machine was 50%. 

The cutter cost per foot of tunnel was $50, and the machine cost was 
slightly over $1 million. 

The bored surface of this tunnel was of such excellent quality that no 
final concrete lining will be necessary. This will result in a consider¬ 
able savings in the total cost of the tunnel. 


Job No. 9 


Another deep tunnel sewer project for MSDGC is the Southwest Intercep- 
ter Sewer 13A, 17,553 ft. long and 13 ft. 10 in. in diameter. This 
tunnel is being bored in hard limestone with a compressive strength of 
15,000-to 24,900-psi. This project began in 1969 and was completed 
in September 1970, seme 4 months ahead of schedule. 

The mole used on this job was a Robbins with a thrust of 890,000 lb. 
The cutterhead was equipped with 27 disk cutters with a center tricone 
cutter. 


The average penetration rate was 5.5 fph. 

The bore of this tunnel, like that of job No. 8, will not need the final 
concrete lining. 


Job No. 10 

Another hard rock tunnel being bored at an underground metal mine is at 
the Magma Copper Mine, Superior, Ariz. This 12-1 /2-ft.-diam. tunnel 
will be used as a haulageway. This operation began in September 1969, 
and 6,031 ft. of the total 9,400 ft. had been bored as of October 1970. 

The rocks encountered were dacite with a compressive strength of up to 
30,000 psi, and quartzite with a compressive strength of 49,000 psi. 
Although in most of the bore the rock is competent and stands without 
support, occasional loose rock, faults, and cavities have slowed progress. 

The Lawrence mole used on this job is similar to the other Lawrence moles 
already described with a thrust of 1,500,000 lb., a torque of 450,000 
ft. lb., and a rotary speed of 9 rpm. The cutterhead was equipped with 
disk cutters which have tungsten carbide buttons mounted on the cutting 
edge. 

Initial operation with this machine brought out some difficulties with 
the laser beam guidance systems, but these have since been solved. The 


202 


most serious problems on this job have been geologic hazards such as bad 
roof conditions, faults and cavities. These conditions delayed progress 
until they could be stabilized with roof bolts, grout and shotcrete. 

During this bore, a 200-ft.-long section of very hard quartzite (49,000 
psi compressive strength) was encountered. This hard abrasive rock was 
difficult to bore, and the penetration rate fell to 1 fph. Cutter life 
was also very poor in this section, and a number of cutter changes were 
necessary before it was successfully completed. 

In spite of these difficulties, however, the average penetration rate has 
been 6.2 fph. The best month's advance was 850 ft. and the average 
monthly advance was about 650 ft. 


Job No. 11 

In January 1970, the Climax Molybdenum Mine at Climax, Colo, began 
boring a 13-1/2-ft.-diam haulage drift on the 600 level with a Calweld 
hard rock mole. This is the first hard rock machine produced by Calweld 
(Figure 10). 

The rock being bored is a quartz monzonite porphyry with a high fracture 
density. Our laboratory tests gave an average compressive strength of 
only 5,700 psi. This low strength was caused by numerous fracture sur¬ 
faces which ran at an angle to the long axis of the core and along which 
the core was prone to separate. Since other sources give the strength 
of this rock at 16,000-to 28,000-psi, it meets our definition of hard 
rock. 

The mole has a thrust of 1 million lb. and a torque of 347,000 ft. lb. 
The 24-in.-diam tricone bit in the center of the cutterhead rotates at 
25 rpm, and the outer section, equipped with 16 tungsten carbide button 
cutters, rotates at 8 rpm. 

The rocks being bored are primarily argillites along with some volcanics 
and conglomerates. The argillites have a compressive strength of up to 
35,000 psi. 

The Lawrence mole used on this job has 600 hp available to drive the 
cutterhead (Figure 11). The cutterhead rotates at 9 rpm and is equipped 
with tungsten carbide studded disk cutters. 

The mole has averaged 5 ft./hr. and completed 75 ft. on the best day. 
Total footage bored as of October 3, 1970, was 3,500 ft. 

Subsequent to the presentation of this paper, this mole was pulled off 
the job after completing some 6,000 ft. of tunnel. This action was 
reportedly taken because of low penetration rates and excessive main¬ 
tenance requirements. Both of these problems were probably a direct 


203 


result of the very hard rock being bored, now estimated to be in the 
35,000-to 40,000-psi range. 


SUMMARY 


PERFORMANCE DATA 
Penetration Rates 

i 

The instantaneous boring rates of tunneling machines in hard rock show 
a remarkable similarity regardless of the tunnel diameter or rock type. 
The machines studied in this report have achieved instantaneous boring 
rates ranging from 1 to 6 fph with an overall average of from 3 to 4 fph. 
In the hard abrasive rocks, such as quartzite or sandstone, the average 
penetration rates are lower than for the less abrasive rocks, such as 
limestone or dolomites, because of increased maintenance requirements 
due to increased cutter and machine wear. Using a figure of 50% as the 
average availability of these machines, a rate of about 20 ft./shift is 
average. The maximum footage in hard rock is about 1,500 ft./month. 


Boreability 

The most successful hard rock boring was done in nonabrasive rock such 
as limestone, dolomite and dacite, with average compressive strengths 
of less than 30,000 psi. Rocks with strengths of up to 50,000 psi have 
been bored, but only for short distances. The upper limit of economic 
boreability in most rocks is 30,000 psi compressive strength. All hard 
rock tunnels to date have been in the 9-to 13-ft. range. 


Cost 

Cost data were extremely variable because of the large differences in 
rock strength, rock abrasiveness, labor, size of job, etc. What little 
cost data were available showed direct tunnel excavation costs to be 
between $13 and $38/cu. yd. of material excavated with an overall aver¬ 
age of $27. 

While cutter costs were rarely given, they formed a substantial part 
of this excavation cost. Cutter costs given by machine manufacturers 
ranged from $3 to $9.50/cu. yd. of material excavated with an overall 
average of $6.30. 

Capital cost was also a major cost factor in tunneling. Since the 
machines are essentially custom made, they must be amortized over the 
length of a single project. Capital cost can be roughly estimated at 
either $1,000/hp or $50,000 times the cutterhead diameter in feet (10). 


204 



For Jarva Moles the first method gives the best cost estimate. 


Energy Efficiency 

1 he efficiency of a fragmentation process is usually determined by a 
parameter known as specific energy. Specific energy is the energy re¬ 
quired to break out a unit volume of rock. The units we used were lb. 
in./in. 3 or after cancelling terms lb./in. 2 (psi). To calculate this 
parameter we used the manufacturer's specification for torque and rotary 
speed along with the instantaneous penetration rate. To avoid the neces¬ 
sity of conversion factors in the formula, torque was given in (in. lb.), 
radius in (in.), and the penetration rate in (in./min.). The formula 
used was as follows: 

Specific Energy = torque x rpm x 2^r _ 

-rr xradius 2 x penetration rate 

The specific energy for eight of the 11 tunnels investigated ranged 
from 9,400-to 17,250-psi with an overall average of 14,325 psi. The 
ratio of specific energy to compressive strength for these same eight 
jobs ranged from 0.37 to 0.72 with an overall average of 0.54. Thus 
for the majority of tunnels investigated, the average specific energy 
was approximately 54% of the compressive strength of the rock being 
bored. This value agrees with those calculated by other researchers. 


Quality of the Opening 

The quality of the machine-bored openings were in most cases very good: 
i.e., they were on proper line and grade, had little overbreak (5% or 
less), and were stable. Undoubtedly the fact that the tunnels were 
driven in hard rock largely accounts for the stability of the openings, 
but where a comparison could be made with conventional methods, the 
bored opening was always the most stable. Of all the tunnels bored in 
hard rock, over half required little or no support, while the rest re¬ 
quired only minor roof bolting and shotcreting. 

The most outstanding examples of this were the MSDGC sewer tunnels in 
Chicago (Job Nos. 8 and 9) where the quality of the opening was so good 
that no final concrete lining will be necessary. The smooth rock sur¬ 
face, with a compressive strength of 15,000-to 28,000-psi, is far 
stronger than the best concrete lining would be. The elimination of 
these linings will result in a significant savings in construction costs 
for these tunnels. 


INADEQUACIES IN MACHINE BORING 

From the case histories already described, it is apparent that while 


205 



the tunnel boring machine has made notable advances in both the speed 
of boring and the ability to bore increasingly harder rock, there are 
many areas where improvements are needed. To summarize the U.S. ex¬ 
perience with machine boring, we will use some of the findings of the 
OECD Advisory Conference on tunneling (6j. 

From over 600 replies to a questionnaire on tunneling, the most serious 
deficiencies of tunnel boring machines (in order of importance) were 
(1) higher cutter costs, (2) the lack of flexibility in meeting changing 
rock conditions, (3) the low reliability of the machines, (4) the in¬ 
ability to bore hard rock, (5) the lack of an integrated support sub¬ 
system, (6) the inability to bore other than a single-size circular¬ 
shaped tunnel, (7) the large bulky size of the machines, and (8) the 
poor maneuverability of the machines. 

High cutter cost and frequent bearing failures were listed as the most 
serious deficiencies, especially in hard abrasive rock. Cutters, bear¬ 
ings, and seals were criticized for both poor design and poor materials. 
Bearing failure was aggravated by lubrication problems and poor seals 
which failed to keep out contaminants. We also recognized that several 
million dollars a year in research are being spent by the oil well drill¬ 
ing industry to improve cutters and seals and this research will continue 
to provide steady improvement in this area. The inability to sense 
cutter failure and the difficulty in changing cutters also complicated 
the problem. The deficiencies are even more serious in hard abrasive 
rock where the cutter cost is the key to the success or failure of a 
project. While absolute costs are difficult to give, one can generally 
assume that at present TBM's are uneconomical in rock of over 30,000 
psi compressive strength. 

The lack of flexibility to operate successfully in a variety of conditions 
such as in changing rock hardness, in a mixed face, in the presence of 
large amounts of water, and in blocky squeezing ground, was cited as a 
serious deficiency. Thus, in bad ground or where rock conditions were 
in doubt, the more reliable drill and blast method was preferred. 

Tunnel boring machines were also cited as having a low reliability 
because of frequent mechanical failures, excessive maintenance require¬ 
ments, and the need for frequent cutter changes. All of these problems 
were further compounded by the poor accessibility to the critical parts 
of the machine. A survey of hard rock jobs shows that an availability 
of 50% is about average. 

«• 

High capital cost was another often-mentioned disadvantage of tunnel 
boring. As already mentioned, cost can be estimated at $1,000/hp or 
$50,000 times the cutterhead diameter. Using these estimates, a tunnel 
boring machine will cost two or more times as much as conventional tun¬ 
nel driving equipment. Since, in most cases, the cost of the machine 
must be written off on one job, tunnels of less than 1 or 2 miles, de¬ 
pending on tunnel diameter, are doubtful projects. With used machines 


206 


F 


becoming available, however, this restriction does not automatically 
apply (10). 

The inability of tunnel boring machines to bore hard rock without exces¬ 
sive cutter costs was another major criticism of this method. This 
factor has been discussed under cutter cost. Tunnel boring machines are 
attempting harder and harder rock, and today's hard rock job will be 
performed easily in the future. At present the upper limit of bore- 
ability is approximately 30,000 psi, although for short distances rocks 
of 50,000 psi have been bored. Much also depends on the abrasiveness 
of the rock. The more abrasive the rock, and by this we generally mean 
the quartz content, the more expensive and harder to bore. 

The machines were also found difficult to maneuver and could not be made 
to negotiate sharp changes in line or grade. While some machines have 
successfully bored on grades of 27 degrees and some are able to bore 
curves with a minimum radius of six times the tunnel diameter, most are 
limited to boring a minimum radius of 10 to 20 times the diameter of the 
machine. The bulkiness of the machines is also criticized, especially 
in smal1-diameter tunnels. Such tunnels do not offer enough room to 
perform maintenance or repair work on the machines. This fact prevents 
TBM's being used in tunnels less than 80 in. in diameter (10). 

The last major criticism or deficiency noted was the lack of an integrat¬ 
ed support system to hold the ground as the machine is advanced. Many 
machines now have a small shield behind the cutterhead to give imme¬ 
diate support and some have roof drills behind the cutterhead to install 
roof bolts if necessary. Many industry people feel that a machine cap¬ 
able of applying a thin coat of shotcrete to the tunnel roof as the 
machine is advanced would provide good temporary support. 


RAPID EXCAVATION—THE FUTURE 


The recent OECD Advisory Conference on Tunnelling in its Report on 
Tunnelling Demand (5) indicates that an estimated total of about 188,000 
mi. of hard-rock tunnels with an excavated volume of about 4.4 billion 
cu. yd. are expected to be built during this decade in the 18 reporting 
OECD nations. This figure represents a 450% increase in length and a 
210% increase in volume over hard-rock tunneling in the past decade. 
These projections demonstrate the needs facing those engaged in frag¬ 
mentation of hard rock. Significant increases in tunnel construction 
will confront those persons directly concerned with utilities, novel 
underground structures, rapid transit tunnels, and underground parking. 
Only in hydroelectric-power generation are these needs expected to 
decrease. 


207 


SATISFYING THE DEMAND 


With demands for hard-rock excavation of the magnitude mentioned facing 
us during the 1970‘s, it is apparent that new sophisticated techniques 
must be used to supplant or improve on those historically applied. 
Conventional tunneling must give way to various forms of continuous 
fragmentation-^ new generation of tunnel boring machines. 


Novel Methods 

Although the tunnel borer in its familiar form is expected to dominate 
the scene, new hybrid excavators will make their debut. In the eary 
seventies we can look for a combination of mechanical and hydraulic 
fragmentation using powerful continuous jets or water cannons. Plans 
for such a machine are already advanced and cooperation between Exotech 
and the Calweld Division of Smith International, among others, may 
speed the process of this concept from design, development, and testing 
to an actual application. 

In addition, entirely new concepts for tunnel boring may be applied 
later in the seventies after a suitable gestation period. Continuous 
rapid fire ballistic systems may satisfy the energy requirements for 
breaking hard rocks at high rates of advance. Thermal or electrical 
methods using stresses induced by lasers, plasma jets, microwave heating, 
and dielectric or induction heating, alone or in combination with other 
methods, may revolutionize the state of the art. Not to be overlooked 
is the potential of sonic energy. Chemical reagents may be applied to 
assist the mechanical fragmentation process in specific situations. All 
this speculation has been directed toward the rock breakage process. No 
attention has been paid to the total system concept. 


Daring Innovation 

These methods of gragmenting rock are not necessarily "far out" or 
"blue sky." Most have their roots in antiquity as described by Georguis 
Agricola in De Re Metallica (1_). The challenge will be for modern 
engineering to tame the awesome forces involved as needed to speed the 
job of excavation. Operators, contractors, owners, and manufacturers 
will be called on to make increasingly daring attempts with unfamiliar 
equipment and to face the attendant problems. 


PROBLEMS WHICH MUST BE ANTICIPATED 

The diffuculties imposed by the subsurface environment will not be new 
to the tunnel experts. The greatest difficulty may be to impress these 
constraints on people unfamiliar with the environmental problems of 
inner space. But after all, the hostile environment of outer space was 
even more formidable, and has not proved insurmountable. The technology 


208 


of outer space must be brought to bear on the problems of inner space-- 
the hidden dimension. 


Health and Safety 

All fragmentation systems have certain common basic requirements. The 
opening must be supported or self-supporting to prevent injury or equip¬ 
ment damage from fal1-of-ground. If rapid methods of tunneling are 
developed, the support subsystem must receive commensurate attention so 
that it is compatible in every respect. The system for support erection 
must be safe, as well as speedy. 

Workmen and equipment must be protected from flooding, which has account¬ 
ed for a myriad of difficulties in the past decade. The dewatering sub¬ 
system must be compatible with the primary system of fragmentation. A 
hydraulic fragmentation system would require a compatible dewatering 
subsystem which might serve double duty as a materials handling system, 
to remove muck in slurry form. 

Temperature and air quality in the working area must be maintained at 
levels compatible with good health and efficient functioning. Systems 
employing thermal stressing may require a novel air-conditions sub¬ 
system or the application of space suit technolgoy. 

The rapid pace of excavation will, in some cases, require high-speed 
underground systems for materials handling. Designers striving for 
rapid removal of muck and rapid delivery of supplies must put safety 
first. 

Good visibility is extremely important for safe, efficient operations. 
Novel systems may create dust, mist, or haze which, if not controlled, 
will add serious constraints to these systems. 

Present-day problems which can guide future systems engineers include 
the congestion often encountered on tunneling jobs. Equipment im¬ 
provement should consider more compact, lighter weight equipment. Any 
equipment proposed for underground use must overcome the problems of 
hostile environment which renders much present-day equipment unsuitable 
for use underground. 

Experience during the past decade has shown that it is particularly 
important to be able to predict potential changes in rock conditions 
before they are actually encountered. The rock conditions dictate 
the ground-support requirements. Excessive water and major faults 
may bring excavation to a sudden halt. Either rapid boring systems 
must be designed with adequate flexibility to cope with severe changes 
in conditions or sensing equipment must be developed which is capable 
of predicting conditions far ahead of the advancing face. 


209 


high noise levels reduce worker efficiency, impede effective communica¬ 
tion, and if intense enough, cause permanent damage to the ears. For 
many novel systems, this problem deserved immediate and serious atten¬ 
tion. Health and safety constraints, if not considered at an early 
stage of equipment development, could easily spell failure for an other¬ 
wise promising fragmentation system. 

Electrical accidents are all too common, and electrical systems should 
be examined closely for shock and fire hazards. A small underground 
fire often has disastrous consequences, and tunnel boring operations of 
today have not been exempted from these types of disasters. Only care¬ 
ful and imaginative engineering will provide a desirable and complete 
rapid excavation system. 


210 



Forward Thrust Cylinders 
Muck Bucket 


Support Leg 

. Torque Arms 

Hydraulic Pump Motor 


Muck Deflector 

Muck Ring- 

Muck Bucket — 
Bearing Housing— 

Torque Arm-- 

Electric Meter Panel 
Hydraulic Controls- 
Main Frame- 


A Jarva Tunnel Boring Machine Showing Important Machine Features. Fig. 1 
(Courtesy, Petroleum and Mining Div., G. W. Murphy Industries) 




Step 1: Start of boring cycle. Machine clamped. Step 2: End of boring cycle. Machine clamped, 

rear support legs retracted. head extended, rear support legs retracted. 


Step 3: Start of reset cycle. Machine unclamped, 

rear support legs extended. 



Step 4: End of reset cycle. Machine unclamped, 
head retracted. Machine now ready for 
clamping and beginning boring cycle. 



The Basic Operating Cycle of a Tunnel Boring Machine. Fig. 2 

(Courtesy, Petroleum and Mining Div., G. W. Murphy Industries) 


211 
























































































































































































































Right View Shows a Reed QC Tungsten Carbide Button Cutter Used Fig. 3 
in Very Hard Rock. Left View Shows a Reed QKC Tungsten Carbide 
Kerf Cutter Used in Medium Hard Rock. (Courtesy, Petroleum and 
Mining Div., 6.W. Murphy Industries) 



The 12-Ft.-Diameter Alkirk Hard Rock Tunneler Used on the Rich- Fig. 4 
mond Water Tunnel, New York, N.Y. (Courtesy, Lawrence Mfg. Co.) 


212 











The 10-Ft.-Diameter Jarva Mark 11 Mole Used at the Adirondack Fig. 5 
Mine, Mineville, N.Y. (Courtesy, Petroleum and Mining Div., 

G. W. Murphy Industries) 



The 13-1/3 Ft.-Diameter Lawrence Ave. Sewer Tunnel, Chicago, Ill. Fig. 6 
(Courtesy, Lawrence Mfg. Co.) 


213 




The 12-Ft.-Diameter Jarva Mark 11 Mole and Trailing Conveyor Fig. 7 
Used on the River Mountains Tunnel, Henderson, Nev. (Courtesy, t 
Bureau of Reclamation) 



The 18-Ft.-Diameter Robbins Mole Used at the White Pine Mine, Fig.' 8 
White Pine, Mich. (Courtesy, James S. Robbins and Assoc., Inc. 


214 






The 1 7-Ft.-Diameter Jarva Mark 21 Mole Used on the Calumet Fig. 9 

Intercepter Sewer 18E, Chicago, Ill. (Courtesy, Petroleum and 
Mining Div., G. W. Murphy Industries 


The 13-1/2-Ft.-Diameter Calweld Hard Rock Mole Used at the 
Climax, Colo. (Courtesy, CALWELD, Div. of Smith International, 

Inc.) 


215 










An 13-1/2-Ft.-Diameter Alkirk Hard Rock Mole Similar to That Fig. 11 

Used on the Dorchester Water Tunnel, Boston, Mass., the Lawrence 
Ave. Sewer Tunnel, Chicago, Ill., and the Magma Mine, Superior 
Ariz. (Courtesy, Lawrence Mfg. Co. 


TABLE 1. - Tunnel Data for Hard Rock Tunnel Boring Projects 


ob 

o. 

Project, Location, 
Contractor or Minins Co. 

Date 

Tunnel 

Diameter 

Tunne1 

Length, 
ft 

Rock Tvpe 

"ompressive 

Strength, 
psi 

Penetration 

Rate, 

fph 

Depth 

Below 

Surface, ft 

Support 

Water 

Inflow 

i 

Sewer lunnel, Chicago, 
Illinois, S. A. Healy 

1956 

9 ft 


Limestone 

18,000 

to 

25.000 

2 to 4 


None 

None 

2 

Richmond Water Tunnel, 

New York, N.Y. Perini Corp. 
and Morrison Knudsen Co. 

19n4 

to 

March 1965 

12 ft 

25,000 

Schist 

25,000 

4 

936 

None 


3 

Inclined Shaft, Adirondack 
Mine, Mineville, New York 
Republic Steel Corp. 

April 1967 
to 

Nov. 1967' 

10 ft 

768 

Magnetit e , 
Hornblende, 
Gneiss 

10,000 

to 

35,000 

1.7 


Rock 

Bo 1: s 

None 

4 

Lawrence Avenue Sewer No.l, 
Chicago, Illinois 

J. McHugh. Healv and Kennv 

March 1968 

to 

Coniinuine 

13 ft 8 in 

25,000 

Dolomite 

18,000 

to 

32.000 

3 to 5.8 

220 

Some Rock 
Bolts 

100 gpm 

5 

River Mountains Tunnel, 

Henderson, Nevada, Utah 
Construction and Mining Co. 

Sep'. 1968 

to 

June 1969 

12 f' 

20,000 

Tu f t s , 

Rhyolite, 
Rhyodacite 

5,000 

to 

23,000 

10 

300 

None 

None 

6 

Development Drift - Star 

Mine, Wallace, Idaho 

Hecla Mining Co. 

Oct. 1968 

to 

Dec. 1969 

9 ft 

500 

Quartzite 

29,000 

4 

7,300 

None 

None 

7 

Development Drift - White 

Pine Mine, White Pine, Mich. 
White Pine Copper Co. 

Nov. 1968 

to 

Continui ng. 

18 ft 

9,000 

Sandstone 

25,000 

to 

31,000 

2.6 

1,900 

60 degree 

Channel on 

4 ft centers 

Mode r a '_e 

8 

Calumet Intercept Sewer 

18-E (MSDGC) Chicago, Ill., 

S and M Constructors 

Apr! 1 1969 

to 

Sept. 1970 

16 ft 10 in 

18,320 

Dolomitic 
Limestone 

" 17,000 - 

to 

28,000 

6 

220 

None 


9 

SW 13A Sewer (MSDGC)Chicaeo, 

11L , Healy Co. and Kenny 
Construction Co. 

1969 

to 

Sept. 1970 

13 ft 10 in 

17,553 

Limestone 

15,000 

to 

25.000 

5.5 

200 to 235 

None 


10 

Development Drift - Magma 

Mine, Superior, Arizona, 

Magma Copper Corp. 

Sep l . 1969 

i'O 

Continuing 

12 ft 6 in 

9,400 

Limes tone, 
Dacite, 

Ouartzite 

12,000 

to 

49.000 

6.2 

500 

Some Rock 
Bolts and 

r » 

11 

Development Drifts - Climax 

Molybdenum Mine, Climax 

Colo.. Cl'max Molybdenum Co. 

Jan. 1970 

to 

Continuing 

13 ft 6 in 

variable 

Quartz 

Monzonite 

Porohvrv 

16,000 

to 

28.000 

4 to 5 

600 

Steel Sets 
and 


12 

Dorchester Wa'er lunnel, 
Boston, Mass. 

S. J. Groves and Sons 

March 1970 

to 

Continuing 

12 ft 6 in 

33,000 

Argillites, 
Volcanics, 
Conglomerates 

Up to 
35,000 

5 

2 30 

None 

300 gpm 


Table 1 


216 






































TABLE 2. - Borins Machine Data for Hard Rock Tunnel Boring Projects 



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217 

































ILLUSTRATION 

Fig. Page 

1. A Jarva Tunnel Boring Machine showing important machine 

features.70 

2. The basic operating cycle of a tunnel boring machine . 70 

3. A tungsten carbide kerf cutter used in a medium hard rock and 71 

a tungsten carbide button cutter used in very hard rock . . 

4. The 12-foot-diameter Alkirk Hard Rock Mole used on the 

Richmond Water Tunnel, New York, N.Y.71 

5. The 10-foot-diameter Jarva Mark 11 Mole used at the 

Adirondack Mine, Mineville, New York . 72 

6. The 13-1/3-foot-diameter Lawrence Avenue Sewer Tunnel, 

Chicago, Illinois . 72 

7. The 12-foot-diameter Jarva Mark 11 Mole and trailing con¬ 

veyor used on the River Mountains Tunnel, Henderson, Nev . . 73 

8. The 18-foot-diameter Robbins Mole used at the White Pine 

Mine, White Pine, Mich.73 

9. The 17-foot-diameter Jarva Mark 21 Mole used on the Calumet 

Intercepter Sewer 18E, Chicago, Ill.74 

10. The 13-1/2-foot-diameter Calweld Hard Rock Mole used at the 

Climax Molybdenum Mine, Climax, Colo.74 

11. An 18-1/2-foot-diameter Alkirk Hard Rock Mole similar to 

that used on the Dorchester Water Tunnel, Boston, Mass., 
the Lawrence Avenue Sewer Tunnel, Chicago, Ill., and the 
Magma Mine, Superior, Ariz. 75 

TABLES 

1. Tunnel data for hard rock tunnel boring projects.75 

2. Boring machine data for hard rock tunnel boring projects ... 75 


218 













REFERENCES 


1. Agricola, Georius, De Re Metallica, Translated from the first 
Latin Edition of 1556 by H. C. Hoover, and L. H. Hoover, 1950, 

Dover Publications, Inc., New York, N.Y. 

2. Garfield, L. A. Tunnel and Shaft Boring at White Pine. SME Fall 
Meeting, Salt Lake City, Utah, September 1969, Preprint No. 69-AU- 
363, 12 pp. 

3. Hendricks, R. S. Hecla Mining Company Case Study - Raise Boring, 
Shotcreting, Tunnel Boring. Proceedings of the 2nd Symposium on 
Rapid Excavation, Sacramento, California, October 16-17, 1969, 11 pp. 

4. Morrell, Roger J., William E. Bruce and David A. Larson. Tunnel 
Boring Technology-Disk Cutter Experiments in Sedimentary and 
Metamorphic Rocks, BuMines Rept. of Inv. 7410, July 1970, 32 pp. 

5. Organization for Economic Corporation and Development. Advisory 
Conference on Tunnelling Demand--!960-1980, Washington, D. C., 

June 22-26, 1970, 160 pp. 

6. Organization for Economic Cooperation and Development. Advisory 
Conference on Tunneling, Report on Hard Rock Tunneling, Washington, 

D. C., June 22-26, 1970, 32 pp. 

7. Peterson, Carl R. Rolling-Cutter Forces. Proc. 4th Conf. Drilling 
and Rock Mechanics, Austin, Texas, AIME Paper No. SPE 2393, 

January 14-15* 1969, 10 pp. 

8. Sperry, P.E. River Mountains Tunnel. Proceedings of the 2nd 
Symposium on Rapid Excavation, Sacramento, California, October 
16-17, 1969, 12 pp. 

9. Tunnel Boring Through Harder Rocks. Engineering and Mining Journal 
v. 161, No. 3, March 1960, pp. 86-90. 

10. Williamson, T. N. Tunneling Machines of Today and Tomorrow. 

Presented to the Highway Research Board, National Academy of 
Sciences - National Research Council, Washington, D. C., 

January 14, 1970, 14 pp. 


219 



















































































































ACKNOWLEDGMENTS 


This Institute was undertaken and implemented through the 
joint efforts of The University of Wisconsin, The United 
States Department of the Interior and The Environmental 
Protection Agency. 

Acknowledgment is made to Mrs. Barbara June Price and other 
members of the Environmental Agency staff for the completion 
of these papers. 


221 


* 


<VU.S. GOVERNMENT PRINTING OFFICE: 1972 484-483/78 ) 





















































































































































































































































































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